A mustard bath is a mixture of mustard powder and other ingredients that people add to a foot or full body bath. Mustard bath benefits may include a general sense of wellness and possible boosted immunity.

This article describes what a mustard bath is and discusses the potential benefits of mustard baths according to scientific research.

It also provides tips on how to prepare a mustard bath at home and outlines the potential risks and side effects of mustard baths.

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A mustard bath is a mixture of mustard powder and warm water that a person uses to soak their feet or body.

A mustard bath contains powdered mustard seed along with other ingredients, such as:

  • essential oils, which may include:
  • alkaline ingredients, such as sodium bicarbonate or baking soda

Mustard baths make the bathwater alkaline due to the addition of sodium bicarbonate or baking soda. Some people claim that alkaline baths are beneficial to health, though there is little scientific evidence to support this claim.

Manufacturers of mustard baths often claim that their products help with the following:

Studies investigating the potential health benefits of mustard baths are limited.

There are very few scientific studies investigating the potential health benefits of mustard baths.

Moreover, it is not clear whether the potential benefits are due to the mustard seed, the other ingredients, or the alkalinity of the bathwater. These factors are discussed below.

Beneficial effects of mustard baths

A 2020 study investigated the effects of a mustard footbath on respiratory tract infections. The researchers hypothesized that the warming effects of the treatment could have a positive effect on health and on participants’ perceptions of wellness, both of which may enhance participants’ immunity.

The researchers instructed the participants to soak their feet in a mustard footbath daily for 6 days. The footbath consisted of water at a temperature of 104ºF (40ºC), to which the participants added 3 tablespoons of ground black mustard seed powder.

The participants answered a standard questionnaire about warmth perception before and after the footbath therapy. Use of the mustard footbath was associated with improvements in various categories, including:

  • sensation of cold
  • exhilaration
  • unwellness

According to the researchers, the benefits of mustard footbaths may be attributable to the following:

  • natural compounds called “glucosinolates” in the mustard plant, which may have antibacterial, antioxidant, and anti-inflammatory properties
  • the thermal effects of combining mustard and warm water, which may have a beneficial effect on perceptions of wellness

Beneficial effects of alkaline baths

Mustard baths typically contain alkaline ingredients, such as sodium bicarbonate or baking soda. Some people use alkaline baths to treat certain skin conditions, such as eczema and psoriasis.

A 2019 study notes that sodium bicarbonate has antimicrobial properties that may help to treat psoriatic lesions. However, this study found that the application of a topical sodium bicarbonate solution did not lead to an improvement in psoriatic lesions.

Nonetheless, the above study involved the use of a topical alkaline solution. As such, it remains unclear whether an alkaline bath may be more effective in treating psoriatic lesions.

Benefits of additional ingredients

The supposed benefits of mustard baths may be partly attributable to other ingredients within the preparation, such as essential oils and spices.

A 2018 randomized controlled trial of 70 participants compared the effects of a footbath consisting of one of the following:

  • warm water and mustard
  • warm water and ginger
  • warm water only

The study found that the addition of mustard and ginger increased participants’ perceptions of warmth in the feet, compared to warm water alone. The findings suggest that both mustard and ginger can increase perceptions of warmth.

Mustard bath preparations may differ in terms of water temperature and volume as well as added ingredients. People may also apply different products to their skin following a mustard bath.

These differences make it challenging for scientists to determine the potential health benefits of mustard baths.

Further large-scale clinical trials are necessary to determine whether and to what extent mustard baths may be beneficial in treating different health conditions.

Many grocery stores and specialty health food stores stock commercially made mustard bath products. Different brands may contain different ingredients and instructions for preparation and use.

However, manufacturers typically recommend soaking in the mixture for 20 minutes. Some also suggest taking a cold shower after soaking.

A person can also prepare their own mustard bath ingredients at home. Mustard powder is a spice that people can find in the spice section of the grocery store. Other ingredients that a person can add to their preparation include:

There is no standard recipe for a mustard bath, and different recipes will call for different ingredients and quantities.

The concentration of mustard powder to water may also differ between recipes. One option for a homemade mustard bath is to add one-quarter to one full cup of mustard powder to a full tub of warm water.

Given that few studies have explored the use of mustard baths, it is difficult to determine the specific risks and side effects of this treatment.

The American Academy of Dermatology (AAD) does not provide specific bath temperature recommendations. Hot baths can dry out the skin, which may worsen certain skin conditions. The AAD also recommends restricting bath time to 15 minutes or less to avoid further drying out the skin.

People with existing skin conditions should not use mustard baths in place of conventional therapies for their condition. Many conditions can worsen without proper medical treatment. For example, untreated psoriasis can lead to worsening skin symptoms and psoriatic arthritis.

A mustard bath is a preparation of mustard powder and other ingredients mixed with warm water, which a person uses to soak their feet or entire body.

Manufacturers of mustard baths typically claim that their preparations can help to soothe and detoxify the body as well as promote wellness.

Existing evidence suggests that mustard baths may provide a warming effect on the skin, which may boost feelings of wellness. However, further clinical trials are necessary to determine the potential health benefits and risks of mustard baths.

Commercially prepared mustard baths are available at most specialty health stores. Alternatively, a person can make their own mustard bath preparation using mustard powder and other essential oils of their choosing.

A person who has an existing skin condition should consult with a doctor or dermatologist before using a mustard bath. Soaking or heating the skin can exacerbate certain skin conditions.