Dr. Bronner's

What Can You Mix with Castile Soap?

What can you mix with Castile soap - Dr. Bronner's Castile Soap carton

Over the years I have received an extraordinary range of questions about mixing stuff with our Castile soaps. There’s a lot of creative thinking going on out there.

But before you get busy with your green self, let me remind you:

Chemistry happens.

As a general rule, do not mix household cleaners together, especially if you do not understand the ingredients. To the best of our knowledge the chart below outlines what we expect to happen based on tests.

I know that you want to toss together your favorite Green-It-Yourself (GIY) ingredients and hope everybody gets along. But sometimes they don’t.

I am not a fan of complicated mixtures. I don’t do complicated. Just give me some Castile soap with an occasional dash of baking soda or essential oils and send me on my way. However, just because I’m not a fancy girl, don’t let me hold you back.

Helping me here is Dr. Vartan Libaridian, Dr. Bronner’s chemistry and R&D consultant. The chart below gives you both my lay analysis and Dr. Vartan’s scientific breakdown.

IngredientLisa BronnerDr. Vartan
Alcohol (aka isopropyl alcohol, the other IPA)Alcohol is an antiseptic which is commonly used among other things to clean needle sites or cleanse wounds (ouch!). I get that someone might want to take one cleaner (soap) and another cleaner (alcohol) and put them together to make one super cleaner. Better to do a one, two punch: wash with the soap and then spray with the alcohol. This is also the CDC’s recommendation for cleaning and disinfecting.
The overall cleaning effect of soap is not affected, at least up to 5% of IPA. Above that concentration, there is a dramatic decrease of foaming, the solution becomes cloudy, and the alcohol interferes with micelle formation. Although IPA increases slightly the cleaning capability of the soap, it also kills the foaming effect of the Castile Soap. It is a fine line. I would recommend not to add more than 5% of alcohol in the blend. This applies to all alcohol containing products: vodka, cognac, Ethanol, IPA, …
Aloe Vera
If you picture “aloe vera” as an enticing green gel, you have been grossly misled. The real thing is slimy and turns mustard yellow and stains like nobody’s business. That being said, pure aloe applied to skin straight from a plant provides highly effective sunburn relief. However, when I combined the Castile with just a bit of the pulp inside my aloe frond, it gelatinized the whole amount of soap. Think “mucousy.” Very unappealing. Better to apply aloe vera after you wash. Aloe vera has at least 75 active ingredients including saponins, vitamins, amino acids, salicylic acid. However, adding this material either in powder or in solution (gel) form to the liquid soap does not give the soap any added value. The brief contact of the liquid soap with aloe vera on the skin will not leave any aloe residue, and aloe requires prolonged contact to do its work.
Baking soda
Baking soda adds a soft abrasion to the cleaning power of the soap, which makes it a good scrubber for grimy sinks and laundry. In laundry, it is a whitener and deodorizer. It also buffers the Castile Soap, protecting it from acidic substances that might affect its pH.
I don’t know why you would want to combine the Castile Soap with bleach. If you’re using the Castile in an effort to be safer, you’re undoing that effort by adding bleach, which causes everything from obstructive lung disease to burns to environmental contamination. Hypochlorite                 Soap
NaClO     +          R-(CH2)n-COOK
pH 12-13                   pH 9-9.5

When blended, Na [sodium] displaces K [potassium], thus creating R-(CH2)n-COONa. This is a hard soap formula. This doesn’t last too long, and eventually it dissolves. In summary, the soap stays as soap, with both K and Na soap coexisting, but at a higher pH. It can be irritating to the skin.
Borax is an effective cleaning agent, but I don’t like it. Combining it with Castile Soap doesn’t change this. Borax is praised because it is sustainable and biodegradable and old. But it is not non-toxic. It is irritating to the skin, dangerous if inhaled, and has been linked to reduced sperm count in men and reduced libido in women. It should be kept well away from children and gloves should be worn when handling it. Borax may have some beneficial effects when combined with Castile Soap. It has a pH of 9.3, similar to that of the soap. It buffers the Castile Soap, protecting it from acidic substances that would break it down, thus helping the cleaning process. 
Castile SoapCombining Castile Soaps is a fantastic thing to do to achieve your perfect scent. All the soaps in our Castile line have the same soap base with different essential oils added, except for the unscented, which has a higher ratio of saponified olive oil. My dad had his “Euco-Peppo Bear Wash,” a blend of Dr. Bronner’s Peppermint and Eucalyptus which he used for washing our dogs. A favorite blend of mine is Citrus & Almond.
Citric AcidUsually the thought behind adding citric acid to Castile Soap is to bring down the pH. However, acid will react with the soap itself and break apart the soap molecule. You’ll be left with an oily mess. “But your ingredients list citric acid!” Yes, we add carefully apportioned amounts of citric acid in order to catch any unreacted hydroxides from the soap making reaction. Adding any more citric acid than we’ve already added will reverse the reaction.
Coconut milk
This combo is all about making a more moisturizing shampoo. It does reduce the cleaning ability of the soap because some of the soap molecules are busy chasing the oil molecules in the milk, but there can still be some cleaning power available. See notes on “Oil” below.
Club Soda
I’m not really sure of the goal of combining this with castile. Maybe because I suggest using club soda to clean windows. Once again it’s the idea that if each are good then both together must be better. Not really though.
Total waste of money and time. The addition of carbonated water at pH 3-4 with soap will release Carbon Dioxide. Nothing else. Bubbling soap. Very unstable. 
Epsom SaltEpsom salt is magnesium sulfate and has a range of therapeutic benefits. However, it is slightly acidic, which brings us back to the idea of acid/base reactions. (See my post, A Word of Caution About Vinegar & Soap.) Soap is a base, aka an alkali. Because of this Epsom salt does react with Castile soap. It is not a dangerous reaction, but it undoes the benefit of both substances. Use them separately. Not together. Epsom salt is not compatible with Castile Soap. Magnesium sulfate (Epsom salt) has a slightly low acidic pH, around 6. The Castile soap has a pH of around 9. Adding the magnesium sulfate reverses the soap and releases the fatty acid, producing visible flakes of oil.
Essential OilsEssential oils have a lot to add to cleaning solutions both for personal care and for house care. They can give you a personalized scent and add therapeutic qualities. Avoid the trap of thinking that if a little is good, then more is better. Some essential oils are pretty potent. Do research on each type, as they have very distinctive properties.
Any essential oils can be added. They might cloud out the Unscented Baby Mild Soap.
Whether you’re looking to thicken the soap or make it smoother, keep in mind that the soap already has naturally occurring glycerin in it. More glycerin doesn’t increase the efficacy of the soap, but if it makes you happy, go for it.
Adding glycerin increases moisturization potential of the soap, but above 2-3% it decreases foaming properties.
Hydrogen peroxide
Hydrogen peroxide is a little misleading, all coy and subdued in its modest brown bottle. It’s a mild antiseptic on cuts and has an abundance of other uses. But when a chemist uses the word “explosive”…

Combining these two doesn’t boost the effectiveness of either. Another myth of thinking if both are good, together they’d be better. They’re not.
This material can be dangerous if the customer uses concentrated hydrogen peroxide (30% concentration or higher). Mixed with Castile Soap, it releases oxygen. If there is a heat source next to it, it can be explosive. Usually, the hydrogen peroxide that is used to clean wounds is at 3% concentration. In this case, the danger is minimal. When mixed with the soap, the hydrogen peroxide brings no antibacterial benefit. Hydrogen peroxide is acidic so any contact with alkaline soap will cause it to dissociate into water and oxygen. You are basically destroying the peroxide molecule. 
Lemon juiceLemon juice is an excellent addition to your green cleaning toolbox, but like vinegar (see below), not a good partner for soap. The acidity of lemon and other citrus juices quite literally undoes Castile Soap – a process we call unsaponification. The resulting goopy mess renders the soap ineffective at best, an oily mess at worst. While citrus juices are pulled from the pulp, are water-based, and acidic, citrus essential oils are extracted from the rind of the fruit, are oil-based, and are pH neutral. They do not react with the soap and are great additions.
I am intrigued by the discussion of oatmeal face masques, dry shampoo, and exfoliators. I had no idea. There is no problematic reaction in blending oatmeal with Castile Soap. My only concern is clogging the plumbing. If I do try a face masque or some such, I’ll rinse it off in the kitchen with the garbage disposal.
Oil – Jojoba, olive, or coconut The idea here is to make the soap more moisturizing. I get that. But keep in mind that soap grabs hold of oils. This is its primary purpose. So if you add too much of any oil, then the soap is going to be busy chasing the oil you’ve added instead of the grime on your body. For deeper moisturizing, wash with the soap and moisturize afterwards.Any of these oils can be added. They make the soap superfatted, which means it contains oil that has not been turned into soap. More than 0.5% – 1% is not recommended.
OxycleanThis is another effort to give the castile an added boost. Oxyclean is a combination of hydrogen peroxide (see above) and washing powder (see below). Might as well just reach for the washing powder.This is another effort to give the Castile an added boost. Oxyclean is a combination of hydrogen peroxide (see above) and washing powder (see below). Might as well just reach for the washing powder. Oxyclean contains hydrogen peroxide and sodium carbonate. Hydrogen peroxide as stated earlier will be dissociated into oxygen and water. No benefit.
Sodium carbonate will be useful in softening the water. 
Sal Suds with Castile Soap
I’m not sure why you would want to do this. Again, it’s the idea that if both are good separately, then together they must be even better. It’s unnecessary, but chemically speaking there are no adverse effects. Although there is no interaction between the 2 entities, I don’t see any beneficial effect. For sure Sal Suds is more aggressive on the skin.
Chemically speaking “salt” is a category, not a specific substance. However, most people are thinking of “sodium chloride” which is common table salt, and the base of Sea Salt. Castile Soap does not react with sodium chloride, and mixing the two together can make a great exfoliating scrub. Since salt is coarser than sugar, do not use this on sensitive skin. Great for elbows and feet, though. As a category, “salt” is the result of reacting an acid and a base. Soap itself is another kind of salt, as is Epsom salt (see above for reaction).Salt increases the viscosity of the Castile Soap to a certain extent.
Sugar is a natural humectant, which means that it draws moisture into our skin. This is why we use it in our Organic Sugar Soaps. You can make a lovely scrub by mixing it with Castile Soap.
Here’s a whole post I wrote about this one way back in 2011. Vinegar and Castile soap are great separately and terrible together. They’re like the siblings who just can’t leave each other alone. They get all in each other’s business. Vinegar un-saponifies soap. It’s not dangerous, just messy, and ruins the cleaning ability of either. The one caveat is if the soap is buffered by something like baking soda, as in this GIY Soft Scrub recipe.
Vitamin E (tocopherols)
Mixed tocopherols – aka vitamin E – is perfectly fine to mix with Castile. These are the antioxidants we use in our soaps. For personal care, vitamin E is usually recommended for anti-aging properties. For house care, mixed tocopherols is an antioxidant in GIY solutions. Either way, it’s fine to mix with the Castile Soaps to make a solution last longer.
The first time a friend told me she used vodka to clean her house, I thought that would definitely make housework more fun. However, she put in a spray bottle, not in a glass. While alcohol is an antiseptic, the concentration of drinking alcohol is not high enough for cleaning. If you decide to use it, see the above section on mixing it with Castile. I can think of better uses for vodka.
I did not specifically mix soap with vodka, since this is not a common material that I carry in the lab. (See discussion on alcohol)
Washing soda
Washing soda, or sodium carbonate, is similar to its culinary cousin Baking Soda, or sodium bicarbonate. This is a common ingredient in homemade laundry detergents. Washing soda acts as a water softener as well as a powerful scouring agent. If you are cleaning heavily soiled laundry like towels or work clothes, this will help you a lot. However, it can be a bit harsh, so I do not recommend using much on regular loads, and definitely not on delicates. It combines just fine with Castile soap.
What about a recipe calling for baking soda AND washing soda AND borax? Well, yes, this will scrub your clothes excellently but I hope you like to go shopping because this will wear down your clothes exceptionally fast.
There is benefit to adding sodium carbonate when you have hard water. In this case sodium carbonate precipitates calcium carbonate thus improving the soap’s cleaning capabilities.

Further reading

This tip and many more are in my book, Soap & Soul: A Practical Guide to Minding Your Home, Your Body, and Your Spirit with Dr. Bronner’s Magic Soaps, available now in hardback on or at your favorite bookseller, and as an eBook and audiobook (read by me!) from wherever you download or listen.  

Download Now!

Castile Soap Cheat Sheet

Dilute! Dilute! OK! But how much? Print this guide!


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Sarah Osagie says:

Thank you. Can i mix castille soap with hydrosol? Maybe like rose water instead of actual distilled water?

Lisa Bronner says:

Hi Sarah- The issue is the pH. Hydrosols vary in pH. If you find one that is pH neutral, it might work, but you don’t want to mix Castile soap with anything acidic.

CuriousClare says:

I tried mixing a teaspoon of epsom salt with Castile soap (in a 2tbsp:1 Cup soap to water ratio) and the whole thing thunder white instantly and became clumpy. I suppose the magnesium messed with some ions in the soap.
Why does this happen?

Lisa Bronner says:

Hi CuriousClare- I’m just learning about this too. It turns out that Epsom salt is acidic. Soap is an alkali, or base. You might remember that an acid and a base cancel each other out. Here the Epsom salt reversed the soap, causing it to release it’s fatty acid. (Not dissimilar from vinegar and soap, which I wrote about here: Both great ingredients, just not together. I’ll be updating this page here shortly.

Donna Blanchard says:

Can you mix 10% fine surfer to Dr. Castile Soap? Thank you.

Lisa Bronner says:

Hi Donna – I’m suspecting a case of autocorrecting here, and that perhaps you’re asking about sugar. If so, you definitely can add sugar to the soap. If “fine surfer” is another product entirely, please give me a run down of what that is, and I’ll give it my best shot!

Lisa Waller says:

Another great idea! Thx. I make a shower cleaner my cleaning crew LOVES. It’s your Castile, washing soda & H2O. Sometimes it clots back up unless I run hot water over the bottle and shake frequently. Will anything help?

Lisa Bronner says:

Hi Lisa- That’s great that your cleaning crew loves the Castile soap! Washing soda doesn’t dissolve in water, which is the cause of the clogging. A method I use is to spray the surface with the All-Purpose spray (1/4 cup in 1 quart of water) then sprinkle baking soda over that. Keeping the baking soda in a shaker jar makes it really easy to use.

Jerrell slay says:

I did exactly what you said about adding oils like jojoba. I added to much, I was hoping I Could use it as a hand wash, or should I just throw it out? Thanks for the post!

Lisa Bronner says:

Hi Jerrell- Unfortunately, I don’t think the jojoba can be saved. It’s best to start fresh.

IM says:

Thank you for all this information. I’m just starting to use castile soaps, and it’s very helpful to read about how to use them properly. But as a chemistry teacher, I have to point out one little inaccuracy: sodium carbonate is Na2CO3 and sodium bicarbonate is NaHCO3. They are not one carbon atom apart as their name might suggest, but instead differ in their numbers of sodium and hydrogen atoms.

Lisa Bronner says:

Hi IM- Thank you for the correction. I’ll make that change. It’s always good to be accurate!

Christian Chretin says:

I use it for hand soap and add a few drops of essential oils in a glass foaming soap dispenser my question is. Is it ok if I put orange peels in it just for decoration or would it spoil the product? Thank you!

Lisa Bronner says:

Hi Christian- For a one-day, special occasion, it would look delightfully festive! But due to their high water content, the orange peels would deteriorate too rapidly for extended use.

Andre says:

Hi Lisa,

Thank you for this article! Others I read don’t go into the chemistry of these mixtures, so it was nice to get that along with your personal experiences. Do you have any advice on common household substances to mix with the liquid castile soap to increase its lather/foaminess?

A loved one suggested Dr. Bronner’s to me to help deal with some long-term skin irritation, and so far it seems to help… but I miss the visual feedback of the lather from the “artificial” body washes I used for so long. I have to work hard to get it from Dr. Bronner’s, and it disappears very quickly for me, especially when diluted.

I was thinking of diluting with baby soap instead of water, but that strikes me as defeating the purpose of using Dr. Bronner’s in the first place. Do you think that’s a good idea, or have recommendations on any other substances I could use?

Lisa Bronner says:

Hi Andre- I’m glad you find the chemistry explanations helpful. The science nut in me enjoys the chemistry side of soapmaking as well. I hear you on the lather. A nice thick lather is appealing. But bubbles aren’t a sign of cleaning power, even though we’ve been trained to think otherwise. They really don’t have any benefit. Lather and bubbles are created by synthetic foaming agents. We don’t add these agents to our soaps, which is why they do not produce the copious bubbles of a conventional body wash. If you add a conventional detergent into the Castile soap, you’ll be adding those synthetic foaming agents as well. To increase the later, try altering your dilution, adding a few drops on a wet wash cloth, or using a foaming pump dispenser with 1 part soap to 3 parts water.

Kayla says:

Hi Lisa, I am new to your blog. I just wanted to point out that the dangers of Borax are completely ill-founded and untrue. Yes, as far as inhalation, it is dangerous, but so are many other things that aren’t harmful if swallowed or applied to the skin. I actually take borax (sodium tetraborate, which is a different type of boron, an essential mineral) as a supplement daily (about a tablespoon dissolved into a big gallon of water, 1 teaspoon of solution taken orally)! It helps to remove fluoride from the body and helps remove hard minerals out of the joints and soft tissues, and back into the bones where they belong. Yes, it’s true, can you believe it? I also have used borax in my natural lotions & creams with beeswax because for some reason it creates a natural and easy emulsification of beeswax, oils, & waters. There was an Australian doctor in the 60s who did lots of research on boron and its effects on arthritis and big Pharma did not like that one bit, and now we have been indoctrinate to believe boron/sodium borate/borax is dangerous.

Lisa Bronner says:

Hi Kayla – Thanks so much for sharing your perspective and experience. This issue is certainly not settled, and Borax does have some utility so long as care is used.

Nannette Stewart says:

Looking for a recipe to mix Manuka Ess oil with your Baby Unscented Liquid Soap to use as a diabetic wound
care (wash). A good friend is diabetic and is wanting to use Manuka as it’s known for its’ anti-bacterial
properties. Thanks much. Nannette Stewart

Lisa Bronner says:

Hi Nannette – I’m not familiar with Manuka essential oil, but from what I’m reading its related to Tea Tree oil, which does have antimicrobial properties. Essential oils are quite potent, so you only need to add a couple of drops to our Unscented Castile soap. Alternatively, our Tea Tree Castile soap already has the essential oils added. Whatever route you go, be sure your friend consults with a medical professional before using.

Jennifer Myers says:

I am looking for a solution to keep my castle soap from turning solid in the cold.
Thank you

Lisa Bronner says:

Hi Jennifer- This is certainly a seasonal thing. The soap is still safe and effective, but to soften it up, place the bottle in a bowl or sink of hot (not boiling) water for a few minutes. I’m not sure how to prevent this other than to try keeping it in a different area of the house. Or possibly wrapping it in a dish towel, although I haven’t tried this personally. If you come across a trick that might help others, please post it here.

Lisa Bronner says:

Hi Jennifer- Giving this some more thought, another option is to use the Unscented Castile Soap. It is the coconut oil that gets white and solid around 58-60 degrees. The Unscented has a higher ratio of olive oil than the other scents, so it would have a lower solidification point.

Karen Daniels says:

I am so happy and relieved to read these rock solid facts from you and Dr. Vartan Libaridian. Now I’m going to educate a slew of DIY cleaning bloggers 😀

Janelle says:

I add tea tree oil and lavender oil to my peppermint soap and it turned to a gel

Lisa Bronner says:

Hi Janelle – How frustrating! There shouldn’t be a reaction when adding essential oils to Castile soap. Sometimes when that happens, we’ve found that the essential oils used aren’t pure oils. Can you give me a few more details about the essential oil you added – were there any other ingredients in it except pure tea tree and lavender essential oils?

Catherine says:

This is great, thanks! Could you share any thoughts on mixing water and castile soap, in an anti-microbe sense? Should there be a preservative added as well seeing as water can so easily breed germs? I’ve been researching for a while and am so confused on the topic of using water in DIY products. Thank you.

Lisa Bronner says:

Hi Catherine – I have never had an issue with water causing a problem with microbes. That being said, theoretically it is possible, based on the cleanliness of water used and how long the solution sits. In our litigious society, most people are going to cover their backsides by mentioning the possibility. Tap water in the U.S. is exceedingly clean of microbes – usually the problems with it lie in the other direction with excessive chlorine and such. I don’t worry about the microbes, and I use RO water to get rid of the additives. I have never added a preservative to DIY solutions. Soap is naturally self-preserving, and that will keep most dilutions safe for as long as it would take you to use them up. However, if you wanted to, you could add a couple drops of vitamin E, which is a natural antioxidant. Or use distilled water.

Lisa Bronner says:

Hi Sherlei – I appreciate your patience. To answer your question we had to do some testing. There is no reaction between the castile soap and colloidal silver.

Grace says:

Hi Lisa – so grateful for your blog and all the pure gold you’ve put here. Thank you! I’m about to order some Sal’s Suds and can’t WAIT. Question: if I mix hydrogen peroxide with Sal’s Suds, is that a safe combo? (I’m attempting to make some homemade laundry detergent with Sal’s Suds and some homemade bleach which uses hydrogen peroxide. I know this list was primarily addressing castile soap…not sure if Sal’s Suds applies to all of these in the same way?) Thank you!

Lisa Bronner says:

Hi Grace – I’m so glad it has been a help to you. I haven’t tackled all the chemistry yet as thoroughly for the Sal Suds and mix-ins. I do know that hydrogen peroxide is pretty unstable and breaks down into water fairly quickly in the presence of an alkali, which the Sal Suds is. My guess would be no, it’s not a useful combination. I will look into this with Dr. Vartan and see what he says.

Shanelle Hudson says:

Thank you so much for this thorough and organized explanation. This information is very helpful for DIYers just starting out and natural makeup/skincare enthusiasts.

Mike shults says:

In interested in combining part distilled water castle soap with jojaba oil and grapseed oil. I straight razor shave and relater and do at least 3 passes. The last pass is an oil pass to clean up the remaining stubble.
How to i combine the water oils, and soap? I’m not looking for a real explosion of foamy suds at all. Just a very thin clear slick formula.

Lisa Bronner says:

Hi Mike – I apologize for my delayed response here. With what you’re striving for, you can definitely combine the soap with water and oil, and give it a good shake before each use. It won’t suds much – possibly not at all, but it will give you that slick feel you’re looking for. As far as ratios go, maybe start with 1:1 on the water and soap, let’s say 1/4 c. of each, and add 1/2 tsp. of each of the other oils? That’s a starting point. Feel free to adjust to your liking.

Paul says:

I got the shave soap. And, it’s great! 2 questions: If washing a beard, with the shave soap; do you recommend using the rinse? Also, is the shave soap gentler than the baby bar? Thanks!

Lisa Bronner says:

Hi Paul – The shave soap is fantastic for washing beards. It draws in extra moisture than our castile – bar or liquid – does. Because it contains that shikakai extract (what makes it so dark brown), it really softens the hair, and the skin as well. I’m actually writing a post this very day about beard care, of all the people I have talked with, none have used the rinse. Many wash with our Sugar Soap (the Shave Soap is an even thicker and more nourishing Sugar Soap) and then they use our unscented Magic Balm for smoothing and control.

Kc says:

I didn’t see citric acid on the list, I’m just curious about that one. I notice it in a lot of household cleaners. Would it be beneficial in any way making a shower cleaning spray with castile soap, water, and citric acid?

Kc says:

sorry – one more question as well. If i wanted to boost my laundry, while using castile or sal-suds as the laundry soap. would I be able to use either baking soda or oxygen bleach powder as a booster?

Lisa Bronner says:

No problem! Baking soda works with both the Castile and the Sal Suds. Check out details about that in the post above. Oxygen bleach powder, of which Oxyclean is an example, isn’t good with either. This is a combo of washing soda (sodium carbonate) and hydrogen peroxide. Hydrogen peroxide is pretty unstable, and the alkalinity of both the Castile and Sal Suds would just break it down. It would be a waste.

If you really like using the oxygen bleach powder, however, you could do a presoak and rinse of your laundry and then wash them with the Castile or Sal Suds.

Lisa Bronner says:

Hi Kc – Thanks for asking! I’ll add it to the list. It’s a no-go for the same reason that vinegar or any other acid doesn’t work. Acids react with the Castile soap, which is alkaline, and break it down.

A savvy reader might raise a hand here and point out that there is already citric acid in our soap. What’s up with that?! We individually test each batch to make sure there are no unused sodium hydroxide molecules running around in it, which would be irritating to the skin. We add the exact amount of citric acid to catch any stray NaOH. Any more citric acid, though, would snag the soap molecules themselves.

Paul says:

Hello. Great post! I really like Dr Bronner’s. How can I wash dry, brittle hair, with Castile soap, without doing it out? Thanks!

Lisa Bronner says:

Hi Paul – Check out this definitive hair washing guide from the Dr. Bronner’s blog. The Castile may not be the best option for you. Instead, try the Organic Sugar Soap or even the Organic Shave Soap for hair washing.

Rebecca Taliaferro says:


I love reading your posts. It has been recommended that I mix 5 oz of unscented castile soap with 5 oz of raw honey for a face and body wash. I would like to know your opinion on this. Thank you.

Lisa Bronner says:

Hi Rebecca – I am intrigued! I am curious to know the purpose of the honey. There is no chemical reaction between the soap and the honey, other than the soap would grab hold of the honey to rinse it away. I’m not sure if combining them at equal volumes, there might not be enough soap to clean anything else off the face. I’d be willing to try it just to see. You could try it on your hands or something first just to see how it feels and how it rinses.

Rebecca Taliaferro says:

The lady who uses this formula is in her 80’s and is Dutch. She said it leaves her skin really soft. Her daughter and family also use this.

I actually bought the sugar soap and really am enjoying it.

Thank you for replying.

Liz says:

Your pages are amazing. You totally go oppositely the so called norm I gather that you are a chemist. Love love your insight.

Margarita Cramer says:

Thank you. I am in love with my general cleaner that involves water, peppermint castile soap, and peppermint essential oil. You made me laugh with the vodka story/recipe.

heather says:

thanks for posting! Some good tips I didn’t know. I do adore adding essential oils to my Dr Bronners Castile, as well as sea salts for exfoliation. in case anyone is interested, I also like diluting it with a bit of distilled organic rose water for my personal care uses. Very gentle and seems to have a softer effect on my sensitive skin after rinsing than when diluted with the water from the tap.

Linda Whitlock says:

How much essential oil would be necessary to scent a 16oz bottle of castle soap?

Lisa Bronner says:

Hi Linda – It entirely depends on the essential oil. Some are more potent than others. Start with maybe 5 drops and shake it up and give it a sniff. Increase from there.

Tiffany says:

Over time, I’ve started using Castile Soup mixed with water for almost all cleaning in my house. However, I have noticed something when I use it in a spray bottle for the counters (and now I use the spray bottle for quick dish washing too). For some reason it makes me (and anyone who comes around while I’m spraying it) cough. Like it kind of gives a choking feeling. I still use it because I know it’s safer than other products, but can you tell me why it’s giving this choking/cough feeling? Am I using too much – or should it not be used in a spray bottle? Just wanting to confirm it is safe used this way. Also, another question, completely different topic – I sometimes mix castile soap, water, and baking soda as a shampoo for my hair. The article says that combo is great for cleaning grime and laundry, is it maybe a mixture I should be using on my hair? I don’t use it every wash, but do use it occasionally when I’m trying to cut out harsh chemicals in my beauty routine (at one point in time I did use it every wash for 6-8 months).

Lisa Bronner says:

Hi Tiffany – Putting it in a spray bottle is perfectly fine. Our lungs by nature reject any foreign vapors and so if you breathe in soap vapors, your lungs are going to object. It could be spray bottle is vaporizing the spray a little too much. See if you can adjust the nozzle to make more of a targeted spray rather than the really misty spray.

For the shampoo, that mixture of soap, water and baking soda sounds fine. You’ll likely need a vinegar rinse afterwards.

Lauren says:

Great tips and reminders of what NOT to do. I think with the trend of the cleaning videos on YouTube, you have people just mixing whatever and calling it natural when you should really just stick to the basics that you have provided over the years – I love your YT videos Lisa!

Lisa Bronner says:

Thank you for the kind words, Lauren! Glad they’re helping. I know everyone’s heart is in the right place, and are trying to do the right thing by mixing stuff together, but I absolutely agree – keep it simple!

Susan says:

Also, you need a Share on Twitter button up there somewhere.

Lisa Bronner says:

Thanks for the heads up, Susan! We’ve had those buttons disappear before. We’re working on figuring out where they went.

MJ says:

Very nice format and article. About borax: it’s a mineral, sodium borate, so isn’t really biodegradable. It’s often mixed with biodegradable ingredients and the labelling may be misleading as to the biodegradability of the mixture. I’m also unclear about its sustainability, because it’s mined (hence the 20-mule-team association).

Small amounts of boron can be beneficial to plants, such as fruits in the rose family, but quite toxic in larger amounts. For this reason, I’ve avoided using borax in houses with septic and/or gray water systems.

Nen Sorensen says:

Thank you very much for this post, I have been using your liquid and bar soaps for 9 yrs now, I love it
Nen Sorensen

Dr. John E. Fortunato says:

I think you should mention that some people react badly to essential oils. I tried your shaving gel and it burnwd my face so badly I had to wash it off.

Lisa Bronner says:

Hi Dr. F – There certainly are sensitivities to essential oils. That is why we have our Unscented (light blue) line of products.

T S says:

Yep, I am embarrassed to say I have tried them all.
However, I must say adding a bit of bleach (don’t use often) to the Sal suds in my white laundry, just seems to boost the “whiteness”.
From now on, Sal suds only! Promise!

Kimberly Dawn Pelle says:

Extremely informative. Now I know why my mixture of Olive Oil, salt and the soap came out weird and with a funky after-smell. 🙂

Blayne says:

I’ve tried mixing certain essential oils to the castile soap, and it actually made the soap thick/bar-soap like. Which essential oils work best?

Lisa Bronner says:

Hi Blayne – One thing to keep in mind with essential oils is to verify that they are pure, and not mixed with some sort of carrier oil or other substance. That could create an entirely different chemical reaction. The most common ones I add to the soap are Citrus and Tea Tree, but considering I’ve named two of the scents we make anyways, that’s hardly surprising. I know people add extra Peppermint, Lavender, Patchouli…

I invite other readers to comment with their favorite oils to add to the soaps!

Carol says:

I’ve been using (and loving ) your peppermint castile soap for years for hands and body. I wash my hands a lot! What I don’t understand is what property of most plastic dispensers interacts with the diluted soap making it degrade faster and thus losing the appealing smell? Every plastic pump bottle I’ve tried does this; worst of all was a plastic aerating foam dispenser.

Since I’ve switched to glass containers my peppermint soap stays fresh a lot longer. I’ve tried diluting with filtered drinking water and had the same problem. Once degradation has occurred in a plastic container, the container is no good anymore. However, in the shower I’d much prefer a plastic container.

The degradation does not occur in the plastic bottles the soap comes in. What’s going on?

Thank you!

Lisa Bronner says:

Hi Carol – There are so many different types of plastic. Some definitely degrade more quickly than others. Some are more photosensitive than others – resulting in faster degradation in sunlight. Glass probably insulates better than plastic as well. I agree that plastic is a better option for the shower. I keep an 8 oz. Dr. Bronners bottle in the shower and refill that from a gallon I keep under the sink. That way I’m sticking with plastic that I know. For more info on our use of plastic, check out this article:

Patricia McGuire says:

Great information to have on hand, however, I think your soaps are wonderful and effective all on their own. I use them for just about everything.

Kate says:

This is excellent info! I have wanted to mix in some of my favorite essential oils to get “my” scent, but have been hesitate until reading this, thanks (Sage – Mint Momma).

Shannon Smith Brennand says:

Lisa, you crack me up! Oh, and this article was informative. I know and understand a bit more now. Thanks!

Lisa Bronner says:

Gotta find the fun where you can! And who says chemistry isn’t fun?

About Lisa Bronner

My grandfather was Dr. Bronner, my family makes soap, and I share ways to use it plus tips on greener living.

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Castile Soap Cheat Sheet

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