Herb library · Spice · Brassica nigra, Brassica juncea, Sinapis alba
Mustard
The seeds of black, brown and white mustard plants, ground into a condiment and pressed for oil. Mustard is a well-known cause of food allergy, and mustard pastes left on the skin can burn it. There is almost no research on it as a medicine.
Traditional use
Mustard has been a condiment and medicine since Greek and Roman times. In India, where Sanskrit writers called the seed sarshapa, the Sushruta Samhita classes white mustard as pungent and heat-making and says it diminishes vata and kapha; mustard oil is a cooking oil and a body oil, and the seeds were used for indigestion. In Europe and India, crushed seed mixed with water was laid on the skin as a plaster for aches and chest congestion. In China the leaves are eaten as a vegetable. Mustard footbaths are still used in German integrative medicine.
Traditional energetics
Ayurveda
Taste (rasa): pungent; potency (virya): heating; after digestion (vipaka): pungent; in dosha theory it balances vata and kapha. An English Translation of the Sushruta Samhita, vol. 1 (1907), Sutrasthanam, ch. XLVI, pp. 478–479 (opens in a new tab)
What studies show
- Insufficient
Colds and feeling warm: small studies of mustard-seed footbaths are only preliminary. In a 2020 pilot study of 139 people with respiratory infections, those who took footbaths for six days reported feeling warmer, and the authors call it a first insight. In a 2021 crossover trial in 17 healthy young adults, mustard footbaths only tended to raise self-reported vitality compared with warm water alone.
- Insufficient
Other medical uses: no clinical trials of mustard as a medicine for pain, digestion or other conditions were found in the sources used here.
Be careful of
Cautions
- AllergyMustard can cause allergic reactions ranging from mouth symptoms to full anaphylaxis, often serious and often in small children, and its allergens survive heat and food processing. The European Union requires mustard to be declared on food labels as one of its specially regulated allergens. It can also be a hidden ingredient in foods.
- AllergyIn a large US food-allergy patient registry, mustard was one of the three most often reported seed allergies after sesame, and epinephrine was given for about a third of reported reactions.
- NoteMustard plasters and poultices can burn the skin. A 2012 case report describes a second-degree burn after a mustard-seed mixture was put on a knee for arthritis pain, and notes that leaving a plaster on too long can cause burns and nerve damage.
- PregnancyNo pregnancy or breastfeeding safety information for medicinal mustard was found in the sources used here. Talk with your clinician first.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“White mustard (Shveta Sarshapa) is pungent in taste and digestion, strong and heat-making in its potency. It gives rise to a condition of parchedness in the system, and diminishes the Váyu and the Kapham.”
“The seeds share its properties, and when powdered and mixed with water act upon the skin and mucous membranes as a stimulant of the circulation, causing heat, redness and pain if the application is short, but vesication and much irritation if too prolonged.”
“A strong decoction of mustard, called 芥醬 (Chieh-chiang), was made to be eaten with meat, and was much relished, as the European eats prepared mustard with his corned beef.”
In scripture
Where the Bible names this plant, and which plant scholars think is meant.
He set another parable before them, saying, “The Kingdom of Heaven is like a grain of mustard seed which a man took, and sowed in his field, which indeed is smaller than all seeds. But when it is grown, it is greater than the herbs and becomes a tree, so that the birds of the air come and lodge in its branches.”
Tristram (1898) identified it as black mustard (then Sinapis nigra, now Brassica nigra), one of the plants on this page, which grows very tall in the Jordan valley. He rejected the suggestion that it was the so-called mustard tree, Salvadora persica. H. B. Tristram, The Natural History of the Bible (1898), pp. 472–473 (opens in a new tab)
He said to them, “Because of your unbelief. For most certainly I tell you, if you have faith as a grain of mustard seed, you will tell this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible for you.
Black mustard (Brassica nigra), in Tristram's identification (1898); "small as a grain of mustard seed" was a saying of the day. H. B. Tristram, The Natural History of the Bible (1898), pp. 472–473 (opens in a new tab)
Sources
- Mustard — an important food allergen? (Tidsskr Nor Laegeforen, 2005) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- A Comprehensive Review on Mustard-Induced Allergy and Implications for Human Health (Clin Rev Allergy Immunol, 2019) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Seeds, Spices — Not Always So Nice: A Report on the Food Allergy Research & Education Patient Registry (J Allergy Clin Immunol Pract, 2026) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Phytocontact Dermatitis due to Mustard Seed Mimicking Burn Injury: Report of a Case (Case Rep Med, 2012) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Use of Mustard Seed Footbaths for Respiratory Tract Infections: A Pilot Study (Evid Based Complement Alternat Med, 2020) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Warm Footbaths with Sinapis nigra or Zingiber officinale Enhance Self-Reported Vitality in Healthy Adults More than Footbaths with Warm Water Only: A Randomized, Controlled Trial (Evid Based Complement Alternat Med, 2021) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.