What Is Castile Soap?

By Jonathan Reich

Castile soap originally referred to soap made with olive oil, instead of animal fat, from the Castile region of Spain. With some changes, castile soap is widely available and is a good choice for many consumers.

Castile soap probably was the first white bar soap.


Although it was originally made with 100 percent olive oil, many soaps known as castile are made with other plant-derived oils as well. Today, a soap made predominantly with olive oil can be called castile soap. Using other oils reportedly improves the lather of the soap.


Castile soap originated in the 16th century and was probably the first example of hard, white soap. It was known as "jabon de Castilla" or to apothecaries as "sapo castilliensis."


Castile soap is moisturizing and gentle to the skin, containing no colors, dyes or detergents, so it can be used for babies or people with skin sensitivities.

Make Your Own

Castile soap is relatively easy to make at home and can be a fun and economical project.

Other Uses

Because castile soap is an effective cleaner, it can also be used as a shampoo and even a laundry detergent. The manufacturing process is much more eco-friendly for castile soap than for these other products.