What is Castile Soap? Why This Classic Cleaner is (Still!) Wildly Popular Today

Kiki Powers

by | Updated: September 27th, 2023 | Read time: 6 minutes

If you prefer safe, natural household products over those made with chemicals and other unhealthy additives, the soap you and your family use daily is a great place to start. Like many health-minded consumers, you may have tried numerous brands and types of soap. However, one old-school cleanser is enjoying a renaissance in popularity, and for good reason − Castile soap.

Overhead View of Woman Washing Dishes Using Castile Soap

What is Castile soap, and how did it originate?

Stepping back in history, we see that by the 12th century, soap makers began to proliferate throughout Spain and Italy. As a result, many cities within these countries become soap export centers to the rest of Europe, one of these being Castile, Spain. When Castile soap hit England in the mid-1500s, it was still an upper-class commodity. In fact, prior to the 18th century, soap of any kind was a luxury for many.

Why was Castile distinguished for soap production?

Among European soap-making centers, Castile rose to prominence above the rest, in part because the city was already renowned for high quality olive oil production, which is a central ingredient in Castile soap, naturally imbuing it with antiseptic, astringent and emollient properties.

How is Castile soap more pure than other options?

Castile soap is one of the earliest, fully plant-based cleansers. Prior to the method of fusing sodium carbonate with olive oil, animal fats, rancid in some cases, were a base main ingredient in traditional soap. As Castile soap was so pure, gentle and effective, it became quite popular with Spanish royalty, among other royal dynasties across Europe.

Castile soap production has since evolved to include other plant-based oils, such as coconut, palm kernel, hemp and jojoba. This safe, natural, biodegradable soap−available in bar or liquid form−is free of animal fats and synthetic ingredients, making it ideal for vegans and the vegan-friendly.

Castile soap benefits for the environment

Castile soap is environmentally friendly from production to application. Not only does this type of soap have a tiny carbon footprint in terms of how it is made, but also, in how it is used, as it has the potential to replace many household and personal care products, resulting in greatly reduced packaging, transport and waste. Nor does Castile soap create problems for plant or marine life in runoff, as it is free of unhealthy chemicals and is safely biodegradable.

Castile soap uses for your daily life

Castile soap is among the most versatile of household and personal care staples. Here are just a few of the many uses for this highly effective natural cleanser:

Kitchen soap

Imagine if you didn’t have to keep buying commercial dish soap in hard plastic containers. Eco-friendly Castile soap is an effective alternative which is cheaper, safer and more gentle than mass-market dish soap products.

To use: Add 1 part Castile soap to 10 parts of water to make a liquid dish soap. Curate it to your liking with your favorite essential oils, such as lavender, lemon, geranium rose, clary sage, sweet orange, or lemongrass. For extra antiseptic and anti-microbial power, include rosemary oil, oregano oil, or combination blends such as lemon-eucalyptus and lavender-tea tree.

DIY face & body wash

Castile soap, mild enough to use on your face, is also imbued with natural properties to help combat bacteria associated with acne. For aroma, choose a lush floral scent or soothing blend, such as this aromatic Peace & Calming formula. For extra cleansing benefits, consider infusing your DIY blend with a few drops of peppermint oil, which will add a lovely clean-tingly feeling, or lemongrass, as both have been shown to kill 22 different types of bacteria.

To use: Add a small amount of Castile soap to a wet washcloth and cleanse your face, rinsing as usual. For dry and/or aging complexions, mix Castile soap 50/50 with Pranarom Facial Cleansing Oil which combines apricot kernel oil with grapefruit & mandarin for a refreshing, moisturizing complexion treatment.

Luxury bath serum

The warm bath is an age-old self-care ritual with benefits on many levels. It is mentally and emotionally nourishing to soak serenely in heated water infused with fragrant salts and oils. It is also physically beneficial, in terms of soothing sore muscles and joints, especially with the addition of therapeutic oils and  Epsom salt. You can easily curate your bath serum depending on how you feel or as a gift for someone else.

To use: Prepare your luxury bath blend by mixing liquid Castile soap in a 1:1 ratio with magnesium oil. To this base, add essential oils as desired. Aromatic, relaxing choices include ylang ylang, rose, jasmine, lavender and geranium rose. If you’re under the weather, you might incorporate this fragrant Immune Defense blend.

Hair and scalp-nourishing shampoo

You would probably be surprised to learn how much money you have spent on shampoo in the last decade. Fancier brands can be especially costly, and yet, are not proven to be more effective than more natural alternatives, such as Castile soap blends you can make yourself.

To use: Simply apply a small among of Castile soap to the scalp and shampoo as usual, rinsing thoroughly afterwards. As with your face and body wash, you can customize this DIY shampoo with beneficial oils and extracts, such as this Pranarom Strong Roots Follicle & Scalp Support Essential Oil Blend.


If it bothers your eco-conscience to keep buying those massive, hard plastic jugs of commercial laundry detergent, you can easily replace them with Castile soap for a greener home and reduce your spending in the process. It’s a safer option as well, given that chemical-based laundry detergents can pose dangers for children and pets, partly due to chlorine, a common ingredient in many laundry soap brands that acts as a toxic respiratory irritant.

As chlorine is heavier than air, it tends to hover in low-lying areas frequented by pets and small children, and can be damaging to the skin, eyes, or other membranes. Given that animals are smaller, with more rapid breathing patterns, they are especially vulnerable to toxic exposure.

To use: Add up to a 1/2 cup of castile soap to a load of laundry. You can customize with aromatic essential oils, singly or in combination. For extra bacteria-fighting, include lemongrass or peppermint oil. For an especially fragrant addition, try this Bouquet Romance Blend which combines essential oils of lavender, ylang ylang, bergamot, orange, patchouli and cedarwood.

Multi-purpose household cleaner

Not only are multi-use products great for the environment, reducing hard plastic and other packaging, but they also save you cash as you need to purchase fewer items. Castile soap is a rock star in this regard, as it can tackle a wide range of cleaning jobs. To make your Castile soap-based household cleaner even more effective against dangerous bacteria and microbes, include eucalyptus, sweet orange, peppermint oil, lemongrass, which were found in one study to be most effective against 22 bacterial strains out of 10 oils tested.

To use: Combine up to 2 cups of soap and essential oils of choice in a quart of water as a cleaning spray for counters, surface areas and other household spaces.

While there are many additional uses for this highly versatile, natural cleaning compound, these ideas should get you started. It can be positively uplifting to find such simple ways to maintain a fresh, sparkling home and high-quality personal care that are also friendly to the budget and our beautiful planet.

Featured Products

Dr. Bronner's Pure Castile Liquid Soap Hemp Eucalyptus
Dr. Natural Pure Castile Liquid Soap
Simple Truth Pure Castile Soap Lavender