What’s the Deal with Castile?

Posted on September 30, 2010 by Stefanie

Dr. Bronner's Castile Soap

Before my local Target stores started carrying the now-famous bottles of Dr. Bronner’s Magic Soaps (complete with their dizzying labels jam-packed with scripture, philosophies, and instructions for both life and soap), I am pretty sure I’d never actually heard of castile soap. Since I started making efforts to green my cleaning routine, however, I see it mentioned all the time. I have to admit, though, that even after I bought my first bottle of the stuff, I couldn’t have told you just what castile soap is. It occurs to me that perhaps some of the rest of you couldn’t either. Let’s remedy that, shall we?

In simplest terms, castile soap is soap made from vegetable oil, rather than from animal fat or synthetic detergents. It originates from the Castile region of Spain (hence the name), where it was made from pure, local olive oil. Modern castile soap is still primarily olive-oil based, but it can also contain other plant oils, such as coconut, palm, soybean, hemp, and jojoba.

Castile soap comes in both solid and liquid forms; the difference between the two is simply the chemical used to saponify (a fancy word for “convert”) the vegetable oils into soap. (The liquid soaps use potassium hydroxide, and the solid soaps use sodium hydroxide, i.e., lye.) [Sidenote: Don't ask me why I go all Bill Nye the Science Guy on you every time I do any sort of ingredient research. Don't put the English major in a box is the lesson here, I guess.]

So that’s what castile soap is. Now, what’s so great about it? Well, a few things. First off, because it’s made from simple, natural ingredients, it breaks down in the environment much more easily than other soaps and detergents, and the waste stream from its manufacturing is less significant as well. In the case of Dr. Bronner’s specifically, the ingredients are organic and fair trade certified, and the packaging itself is 100% post-consumer recycled. Many other brands of pure castile soap are available too, of course (rumor has it that Trader Joe’s has a good one), but since I haven’t actually used them, I’ll admit I didn’t research them as closely.

One of the biggest benefits, however, is castile soap’s versatility. I wouldn’t go so far as to call myself a product whore, but I definitely have enough unnecessary impulse purchases stacked under both my kitchen and my bathroom sink to recognize the value and beauty of simplicity and to strive not to collect three different bottles of something when one will do. Dr. Bronner (yes, he was a real person) said there were 18 uses for his Magic Soap; the Internets assure me there are actually far more than that.

Of the many castile soap suggestions I have heard of, here are a few I can personally recommend:

Body wash: Either lather the bar version up just like any soap or splash a few drops of the liquid onto a washcloth or bath pouf. Since liquid castile soap is concentrated, a little bit goes a lot further than traditional shower gel would. I like Dr. Bronner’s peppermint variety for this purpose. It’s fresh and invigorating, and in the morning, I can use all the help waking up I can get.

Shave gel: Likely because of the natural oil and high glycerin content in castile soap, it works pretty well as a shave gel, without making my skin dry or irritated. (I can wash my face with it too, without feeling any more tight-skinned pre-moisturizer than I do with facial cleansers.) Incidentally, did you know that most traditional soaps on the market have much or all of their glycerin removed, which is why so many soaps dry out the skin? And a lot of the same companies that remove the glycerin from soap sell it back to us separately in products like lotions and moisturizers. There’s some interesting (and mildly maddening) soap trivia for you. Moving on…

Hand soap: Fill an empty hand soap dispenser not quite to the top with water; then fill the rest with liquid castile soap. It’ll lather up like regular liquid hand soap, without the added plastic waste or chemicals. If you want extra anti-bacterial protection, you can add some tea tree oil as well.

Laundry soap: Someday, I will remember to look for washing soda at a store that might actually sell it, and I will then finally try the homemade laundry detergent recipe that Greenists reader Jess has posted in our comments more than once (1 cup borax, 1 cup washing soda, 1 bar grated castile soap — mix up and use two tablespoons per load). Meanwhile, plain liquid castile soap makes a good detergent, too, and the Dr. Bronner’s lavender scent smells just as lovely as the less environmentally friendly lavender vanilla Tide detergent I was so sad to see discontinued last year. Use about a quarter cup for a regular load; add baking soda or borax for extra brightening and whitening power.

General household cleaning: Dilute a tablespoon or two in a bucket of water and use it to clean a multitude of surfaces in your house. You can also use it in place of dish soap, but for that I prefer more suds than castile soap diluted in a sinkful of water provides. If you’re of the “suds don’t equal clean” mindset, however, you may like it just fine.

In addition to all of the above uses, many people swear by castile soap for plenty of things I wouldn’t personally recommend. In my opinion, it makes a terrible shampoo, for example (although people with short or differently textured hair seem to have better luck), and the automatic dishwasher liquid recipe I found online (involving liquid castile soap, water, vinegar, and lemon juice) left my dishes coated with an unappealing white dusty film.

I’m almost equally hesitant to recommend using liquid castile soap to brush your teeth, despite Dr. Bronner’s insistence that it’s a valid option. In the name of thorough research, however, I decided I had to try it, and you know what? With the peppermint variety at least, it wasn’t nearly the horrifying experience I feared it might be. So if you feel so inclined, dab just a drop or two on a wet toothbrush and go to town, but I think I’ll stick with traditional toothpaste for regular use and rely on castile soap only in an unlikely pinch.

I’m sure many of you have a bottle or two of castile soap as a key tool in your household arsenal as well. What are your favorite uses for this magical stuff?


  1. Stefanie, this is so awesome. There have been dozens of times I’ve walked by those crazy castile soap bottles in the store and wondered what the stuff could be used for, but forgotten to look it up by the time I got home. Now I know — and castile soap really does appear to be magic! So many uses!

    September 30th, 2010 at 10:11 am
    Comment by courtney
  2. I get a bottle Dr. Bronner’s magical peppermint soap in my stocking every year. All-one baby! (though I do not live by the all-one principle as I have only ever used it as body wash/hand soap)

    September 30th, 2010 at 10:28 am
    Comment by badger reader
  3. I’m enthused by your post! Thanks Stef. I use Bronner’s all the time, but only for about 3 uses, not for 18+. I’ll be sure to explore it more.

    September 30th, 2010 at 11:27 am
    Comment by Carrie
  4. I LOVE Dr. Bronners. I use it for most of my cleaning. I love it for mopping. Wonderful stuff.

    September 30th, 2010 at 11:30 am
    Comment by Lisa @Retro Housewife Goes Green
  5. My bf swears by it for bathing our dog!

    September 30th, 2010 at 12:27 pm
    Comment by sara
  6. I’ve used my Dr. Bronner’s as a shampoo and found it quite acceptable.

    September 30th, 2010 at 1:41 pm
    Comment by Deborah
  7. My sister uses it in homemade laundry detergent and it smells great! I’ll have to get the recipe for you.

    September 30th, 2010 at 3:42 pm
    Comment by Pants
  8. Oh my goodness, thank you so much. What a well written, enjoyable and thoroughly educational post. I just randomly bought some Dr. Bronner’s last week and thus far have only used it to lube up the dog. Now that she smells so much better, I’m bringing it in the house and now have so many great suggested uses for it!

    October 1st, 2010 at 12:02 am
    Comment by Ingrid
  9. I was recently gifted with a bottle of Dr Bonner’s. I discovered that dabbing it on full strength took out a blood stain better than anything I’ve ever tried. It was also on white fabric and there was nary a trace left behind. I suppose there might be a difference between one fabric to the next, but I can’t comment on that.

    October 1st, 2010 at 11:42 pm
    Comment by Roxanne
  10. Thanks to the people who brought up using castile soap to wash their pets. That’s another use I read about, but since I don’t have a dog, I couldn’t vouch for it myself. Word has it that the peppermint and eucalyptus varieties even help ward off bugs… on pets and on you!

    And Lisa, I’m glad to hear you like it for mopping. I haven’t tried that yet, but I read some comments saying it can leave a white film on floors. I suppose much like castile soap as shampoo, different people get different results. I’ll have to try it the next time I mop. (Note: I mop as infrequently as possible, so that could be a while.)

    October 3rd, 2010 at 11:20 pm
    Comment by Stefanie
  11. Castile soap is versatile, i hadnt thought about using the peppermint or eucalypt. varieties on pets, what a great idea!
    I carry a full line of certified organic soaps, i started selling them mostly out of necessity, i seem to have a reaction to everything else. Has anyonme tried using them on thier pets ?

    October 6th, 2010 at 8:51 am
    Comment by haluden
  12. Thanks for the breakdown! I was just holding a bottle of this in the store, and reading all the random philosophy scrawled across the label and was turned off by it. It’s good to know that it is a worthy product though.

    October 7th, 2010 at 8:31 pm
    Comment by Amy@GreenGardenista
  13. Castile soap works well as a shampoo or dishwashing liquid if you live in an area with soft or medium-soft water.

    I’ve only ever seen washing soda at Ace Hardware, but it’s at a really good price there so it’s worth going to to buy.

    October 18th, 2010 at 10:16 pm
    Comment by Aisha
  14. i had a friend in school who would swear by the tea tree oil blend of Dr Bronners… as she had had several roomates with less than stellar hygiene habits, the tea tree was great for cleaning both herself and the shower!

    October 20th, 2010 at 3:46 pm
    Comment by emily durkee
  15. I really like the Dr. Bronner’s almond castile!I use it in the shower, to clean the floors, countertops, for dusting…what a pleasant scent it leaves behind!

    December 26th, 2010 at 11:04 pm
    Comment by Melissa
  16. I’m using it as shampoo, and I love it. A little goes a long way, too.

    December 30th, 2010 at 9:44 pm
    Comment by mickey
  17. Castile soap is the third ingredient in “Natural Fruit Tree Spray” for apple maggots, etc. The other two ingredients: any vegetable oil and water. It suffocates the eggs if you spray trees while dormant–now through February in most states.

    December 31st, 2010 at 2:24 pm
    Comment by Katheryn
  18. I love the Tea Tree variety for shampooing. It cleared up a horrible dry scalp I’d been dealing with for years!

    February 21st, 2011 at 1:30 pm
    Comment by Andrea
  19. [...] Bucket of water Two rags A few tablespoons of baking soda, poured into a cup A squirt of dish soap or castile soap [...]

    August 10th, 2011 at 4:01 am
    Pingback by How To Clean Your Car Headlights the Natural Way
  20. I just found a recipe for coconut milk shampoo that uses liquid castil soap. I couldn’t find it anywhere, so I bought the bar and melted it down in a small pot of water. You mix 1/3 cup of Dr. Bonner’s (or whatever you have), 1/4 cup of coconut milk and 1 tsp. of olive oil. I have it all mixed up and will try it out tonight and see how it goes.Just thought I’d share. :)

    March 24th, 2012 at 4:39 pm
    Comment by Jennifer

Leave a comment

Tip of the Day

If It Doesn’t Smell, Don’t Wash It


According to Real Simple, if every American made an effort to launder less — cutting out just one load of laundry a week per household — we’d save enough water to fill seven million swimming pools each year.

So if it looks clean, and it smells clean, call it clean and wear it again. Consider hanging worn clothes out on your clothesline to freshen them up between wearings.

  • Stay-ad

    Support This Site