What Is Castile Soap?

Castile soap is a vegetable-based soap. It's chemical-free and does not have synthetic ingredients or animal fat in it.

The soap originated from the Mediterranean region in Castile, Spain in the 12th century. During this time, it was made from pure olive oil. Today, it's made with plant-based oils such as hemp, coconut, avocado, walnut, and almond.

You can get Castile soup in bar and liquid form. Some products are scented with essential oils.

This article will go over the uses, benefits, and risks of using Castile soap.

Castile Soap

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Uses of Castile Soap

There are many different uses of Castile soap. If you know how to use it correctly, the soap can become part of your personal care routine as well as your cleaning regimen for your home.

Personal Care Uses

If you're looking for a health and beauty product that only has a few simple ingredients, Castile soap might be a good option. Here are just a few ways you can use castile soap on your body:

  • Shampoo
  • Hand soap
  • Makeup remover
  • Shaving
  • Steam bath
  • Teeth cleaner and mouthwash
  • Body soap
  • Deodorant
  • Face wash
  • Foot soak

Diluting Castile Soap

Castile soap is very concentrated and needs to be diluted with water before it's used. When you're getting ready to use it—whether on your body or household surface—make sure to water it down first.

Household Uses

In addition to being part of your personal care routine, a bottle of Castile soap can also be handy for cleaning around your home.

Household uses for Castile soap include:

  • Dish soap
  • Laundry soap
  • All-purpose cleaner
  • Floor cleaner
  • Produce wash
  • Bug repellant
  • Window cleaner
  • Bathroom cleaner
  • Shower and tile cleaner

Does Castile Soap Kill Germs?

There is not enough evidence to prove that Castile soap alone is strong enough to kill bacteria, viruses, fungi, and other germs.

One study that looked at whether Castile soap was good for cleaning surgical wounds found that a simple saltwater (saline) wash worked better than Castile soap did.

Benefits

Castille soap has many uses, making it a helpful cleaner to have on hand.

Here are just a few potential benefits of using Castile soap:

  • Versatility: There are many ways to use Castile soap around your home and on your body.
  • Cost: Compared to other beauty and cleaning products, a bottle of Castile soap is affordable and cost-effective. You can get a good-sized bottle for under $10.
  • Vegan: While Castile soap is not for eating, many people who live a vegetarian or vegan lifestyle prefer not to use any products with ingredients that come from animal sources. Pure Castile soap is vegan.
  • Pet safe: Some cleaning products are harmful to pets but pure Castile soap is non-toxic and safe to use on surfaces where pets are walking. You can also use pure Castile soap to wash your pets. That said, some products have essential oils added to them that can irritate a pet's skin, so be sure to read the labels. If you're not sure if a product is pet-safe, ask your vet.
  • Environmentally friendly: Pure Castile soap has a very small impact on the environment since it doesn't contain additives, preservatives, artificial coloring, or other chemicals that are common in other soaps and cleansers.

Risks

However you choose to use Castile soap, you need to use it properly. Here are a few things to keep in mind:

  • May leave a residue: Castile soap can leave a residue on shiny or hard surfaces, especially when it's used with water that has a lot of minerals in it (called "hard" water).
  • Doesn't mix with acids: Since Castile soap is alkaline, it's not recommended that you mix it with acidic substances like lemon juice or vinegar.
  • Can be drying: If you don't dilute Castile soap with water, it's very concentrated. This makes it hard on surfaces and your skin. If you haven't watered it down enough, castile soap can dry out your skin and cause irritation.
  • Not for color-treated hair: If you have dyed hair, using Castile soap as a shampoo or rinse can strip the color from your strands.
  • May harm household plants: While you can use Castile soap to make a natural insect-killer for plants in your home, if you don't use it properly or use too much of it, you can actually damage your plant's natural protective layers.
  • Expires eventually: Castile soap can last a long time, but it won't keep forever. If you have a bottle hanging out in your cabinet, keep an eye on the expiration date. You'll want to toss it after about three years, at least—after that time, it's likely to go rancid.

Always read the recommendations and instructions for diluting and proper use of the Castile soap that you purchase.

Can You Be Allergic to Castile Soap?

Pure Castile soap is hypoallergenic, which means it's less likely to cause allergic reactions than other types of soap.

However, some people can be allergic to Castile soap's ingredients. Even if you're not allergic to castile soap itself, the products often contain other ingredients that can be allergens.

For example, Castile soap with fragrances and oils added to it can cause allergic reactions. If you have a chronic skin condition like psoriasis or eczema, you will also want to choose soaps carefully.

Check the label of any Castile soap product you're thinking about using to make sure you know what's in it and in what amounts.

Summary

Castile soap is a safe, versatile, environmentally-friendly, and affordable cleaner you can use around your house and as part of your personal care routine.

That said, make sure you look at the list of ingredients and instructions for use on any Castile soap product you choose.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Farmers Almanac. 12 reasons to switch to Castile soap.

  2. Schlarbaum, Jamie P. BS; Warshaw, Erin M. MD, MS. Do it yourself without allergic Contact dermatitis: Safe household cleaning product alternatives, dermatitis: 3/4 2020 - Volume 31 - Issue 2 - p e16-e17 doi: 10.1097/DER.0000000000000503

  3. The FLOW Investigators. A trial of wound irrigation in the initial management of open fracture woundsN Engl J Med. 2015;373(27):2629-2641. doi:10.1056/NEJMoa1508502

By Yvelette Stines
Yvelette Stines, MS, MEd, is an author, writer, and communications specialist specializing in health and wellness.