What Is a Castile Soap?

What Is a Castile Soap?

Castile soap isn’t nearly as well-known as regular liquid soap or body soap, and that’s a shame since it’s superior in practically every meaningful way. Never heard of it? Well, let us handle that and explain what castile soap is, what it can do, and why you should definitely pick up a bottle for your own home.

What Exactly Is a Castile Soap?

A castile soap is a specific variety of soap that's made from vegetable oil instead of animal fat.  Since it lacks animal fat(lye) or other synthetic ingredients, it’s among the most environmentally friendly and natural soaps you can get these days. Castile soap can be purchased in either liquid soap or bar soap form. 

Fun Fact: Castile soap got its name from the Castile region of that country, in fact, which is how it’s known around the world today.

How Is It Made?

As mentioned, castile soap can be made with any type of vegetable oil. Because of world economic factors, the most popular oils to make this soap from include:

  • Castor
  • Hemp
  • Avocado
  • Almond
  • Walnut

There are other options, of course, but these are the ones you’ll see most often. Each oil is distinct from the others and can provide a given soap bottle or bar mildly different properties or different fragrances.

How Do They Work?

This alkaline property allows castile soaps to clean a variety of things. Like all types of soap, the molecules within the soap liquid or bar have one end of their molecular structure that avoids water and another that attracts it. As the soap combines with the warm water, free-floating atoms drift about the liquid and capture dirt, grime, debris, grease, and anything else that isn’t soluble in water.

These properties are why soaps are often used to clean grease, oil spills, and the like. Castile soap is also non-toxic compared to other modern soaps. In fact, castile soap is so safe that you can clean vegetables with it, provided that you dilute it adequately beforehand.

What Can Castile Soaps Be Used For?

The best castile soaps can be used for virtually any cleaning task you can think of, including:

  • As dish soap. This is perhaps the single biggest use of soap in the modern home. Making a liquid dish soap out of a bottle or bar of castile soap is pretty easy; just combine one part castile soap to 10 parts water, or purchase a pre-made castile-based dish soap.
  • You can use castile soap as a dishwasher detergent in much the same way. This soap won’t be harsh on any of your dishes, and even finer glasses or plates.
  • Castile soap can also be used as a window cleaner. You can easily make a spray of this stuff by adding a tablespoon of liquid castile soap to about a quart of water and combining it in a spray bottle.
  • Shampoo! That’s right; you can use castile soap as a natural shampoo. You can either purchase a premade shampoo product from someone like Green Goo or make your own by mixing a tablespoon of castile soap with some water.
  • Well-loved- Because it's gentle enough to be used as a face wash. In fact, castile soap is known to sometimes prevent acne from cropping up. Just put a few drops of castile soap on your face, scrub and rinse it away.
  • Body wash, of course, is also an option – if it’s gentle enough for your face, chances are it’s fine for the rest of your body. 
  • Laundry detergent. You can use castile laundry soap as a detergent for your clothes by adding about a half cup of castile soap to a normal load of laundry in your washing machine soap dispenser. There are pre-made castile soap laundry detergents available, as well.
  • Vegetable rinse. If you need to clean your fruits and vegetables for pesticides or dirt if you plucked them from your own garden, you can use castile soap to clean them without making their surfaces toxic. Just add a little bit of soap to a bowl of water and rub your produce until they’re clean. Rinse again and you’re all set.
  • Toothpaste. That’s right! You can even use castile soap as a cleanser for your pearly whites in your personal care routine. This being said, the taste isn’t usually something to celebrate; it might be a good idea to pick up a scented or flavored castile soap if you want to use it for this purpose.
  • Pet wash-Using this as a dog shampoo is great to get a nice lather of bubbles you need to clean your dog, just use a couple of squirts. 

What Shouldn’t You Use Castile Soap For?

Although castile soap has tons of benefits and places where you would be smart to use it, there are a few areas where you should avoid bringing castile soap to bear:

  • Never combine vinegar with castile soap. This will leave a white film behind that can take a long time to clean up. Vinegar is naturally acidic, and combining this substance with the alkaline castile soap will produce an oily substance. The same goes for any other acidic product like lemon juice
  • Don’t mix castile soap with any hard water. Again, hard water reacts to the castile soap and leaves a white film residue behind as the soap transforms back down to its oily roots
  • Lastly, we wouldn’t recommend using castile soap as a shampoo if you have color-treated your hair. Chances are high that it'll strip away that color or ruin your hue job 

Why Do People Use Castile Soaps?

Beyond its ability to clean things, castile soap has several benefits that make it better than traditional soap.


For starters, castile soap is much more environmentally friendly. It doesn’t use tons of synthetic chemicals to obtain its cleaning abilities. Instead, natural oils and other elements are mixed together to form an eco-friendly solution.

This also means that it’s totally biodegradable. Other soaps will remain in the environment and act as toxic elements, stagnating growth and poisoning plants and animals. Castile soap doesn’t have any foaming agents, detergents, or synthetic preservatives.


The fact that castile soap isn’t poisonous and is biodegradable also makes it much safer than traditional soap. For instance, your dog licking a bit of castile soap up is no big deal. It’s also a great choice if you’re concerned about exposing your kid’s skin to too many synthetic chemicals, especially when they’re young.


Most castile soap products are pretty affordable. That’s because they’re sold in highly concentrated quantities. You can dilute the soap down to make it last longer. Plus, even though it doesn’t have any artificial preservatives, it should still last for about three years before degrading in quality.

Are Some Castile Soaps Worth Your While?


Take Green Goo’s Unscented Castile Soap, for example. This fragrance-free product provides you with a pure castile soap, all-purpose cleanser that’s ideal for those with sensitive skin. The formula is only made with all-natural oils and aloe vera, shea butter, and rosemary, so it does a great job of cleaning daily surfaces or items and serving as a skin-washing product. 

Or check out the Green Goo Castile Soap Unscented Aloe Baby Wash. This body wash is perfect for those with the most sensitive skin and gives you an ideal cleansing product whose toxicity you don't have to worry about. Even better, it also works as a general cleanser, laundry detergent, stain remover, and more. 

Ultimately, the best castile soaps will only have natural ingredients and be derived from vegetable or plant oils. Never pick up a castile soap that has some kind of synthetic chemical in its formula; what’s the point of ruining something that works fine just as it is?


Overall, castile soaps are fantastic cleaning products that do everything that regular soap does and more. There’s no reason to go back to synthetic stuff when you see the effectiveness and gentleness that castile soap can bring to your home. If you haven’t experienced it, we recommend giving one (two or three) a try!

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