Scientific Name(s): Armoracia rusticana Gaertn., Mey. and Scherb. Sometimes referred to as A. lapathiofolia Gilib. Family: Brassicaceae (mustards)

Common Name(s): Horseradish , pepperrot , mountain radish , red cole , great raifort


Horseradish has been used internally as a condiment, GI stimulant, diuretic, and a vermifuge, and externally for sciatica and facial neuralgia. However, there are no clinical trials to support any therapeutic use for horseradish. Animal data suggest potential antibacterial and hypotensive effects.


Traditional use for colds and respiratory infections was 20 g/day of fresh root. 1 Externally, preparations with 2% mustard oil have been used.


Contraindicated in patients with GI ulcers and in those with kidney impairment. Not recommended for children younger than 4 years of age. 2


Documented adverse effects. Avoid use. 3 , 4 , 5 Use should be avoided during pregnancy and lactation because the allylisothiocyanates are toxic mucosal irritants. Horseradish has abortifacient effects.


None well documented.

Adverse Reactions

Irritant effects on GI mucosa. External use may cause erythematous rash. Horseradish is part of the cabbage and mustard family; therefore, it may suppress thyroid function. The isothiocyanates may irritate mucous membranes on contact or if inhaled. 6


Ingestion of large amounts can cause bloody vomiting and diarrhea. 6


Horseradish is a large-leafed, hardy perennial native to eastern Europe and western Asia. 7 , 8 The plant is deep-rooted, can grow to 1 m in height, and develops clusters of 4-petaled white flowers during the spring. 8 It is cultivated commercially for its thick, fleshy, white roots that have a strong, irritating, and intensely pungent taste. Some hybrids are sterile; therefore, the plant is generally propagated through root cuttings.


Horseradish has been cultivated and used as a medicine and condiment for at least 2,000 years. 7 , 8 , 9 , 10 Early settlers brought the horseradish plant to America, and the plant was commonplace in gardens by the early 1800s. Hardy varieties were obtained through plant selection and grown easily in the Midwest.

The root has a long history of use in traditional medicine. It has been used to treat bronchial and urinary infections, inflammation of the joints and tissues, sinus congestion, and edema. 11 Topically, it was applied to the skin to reduce pain from sciatica and facial neuralgia. Internally, it was used to expel afterbirth, relieve colic, increase urination, and kill intestinal worms in children. 7 , 9

The horseradish root is used as a condiment and may be grated and mixed with other flavorings to make sauce or relish. 9 Young, tender leaves have been used as a potherb and as a salad green. Horseradish is 1 of the 5 bitter herbs (horseradish, coriander, horehound, lettuce, nettle) consumed during the Jewish holiday of Passover.


The medicinal component is the root, which contains mustard oil and mustard oil glycosides. 11 The pungency of horseradish is due to the release of allylisothiocyanate and butylthiocyanate that occurs in combination with glucosinolates sinigrin 12 and 2-phenylethylglycosinolate. The pungency is released only upon crushing. The isothiocyanates are released from glucosinolates by the action of thioglucosidases, which are commonly referred to as myrosinase. 13 More than 6 volatile glucosinolates have been identified using gas chromatography-mass spectroscopy analysis. 14 Other constituents of the root include asparagine, resin, ascorbic acid, and peroxidase enzymes. 8

To preserve the quality of horseradish, the root is commonly dehydrated, freeze-dried, and powdered. 15

Peroxidase enzyme is extracted from the root and is used as an oxidizer in commercial chemical tests, such as blood glucose determinations. 16 The purified enzyme has a molecular weight of approximately 40 kDa. 17

Uses and Pharmacology

Horseradish is widely known for its pungent, burning flavor.

An extract of horseradish has been shown to inhibit the enzyme cholinesterase. 18

Hypotensive effect

It is hypothesized that horseradish peroxidase acts by stimulating the synthesis of arachidonic acid metabolites. 19

Animal data

Intravenous administration of horseradish peroxidase caused a marked hypotensive effect in cats. The hypotensive effect was completely blocked by aspirin and indomethacin, but not by antihistamines.

Clinical data

Research reveals no clinical data regarding the use of horseradish for hypotensive effects.

Antibacterial effects

The antibacterial properties of horseradish are attributed to the isothiocyanates (ie, mustard oils). 20 The growth of bacteria, such as Pseudomonas spp, Escherichia coli , Serratia grimesii , Staphylococcus aureus , and Enterobacteriaceae , was inhibited on incubated slices of cooked roast beef that were exposed to horseradish essential oil and a distillated extract from fresh horseradish root. 21 , 22

Animal data

Dried and grated horseradish root fed in dosages of 100, 300, and 500 mg/kg with food inhibited the growth of Mycobacterium leprae in mice in 1 study. The authors concluded that dried and grated horseradish root increased myeloperoxidase activity of blood neutrophils, enhanced antimicrobial functions of phagocytes, decreased leukocytosis, and normalized total blood cell count in mice with experimental leprosy. The most efficacious dose was 300 mg/kg with food. Therapy duration of 5, 8, and 11 months produced no toxic effects on the functional activity of the liver (alanine and aspartate transaminases) in control and intact animals. 23

In a prospective, randomized, double-blind, placebo-controlled trial, patients with chronic urinary tract infections (UTIs) were randomized to receive an herbal drug containing horseradish root 80 mg and nasturtium 200 mg at a dosage of 2 tablets twice daily or placebo for 90 days. The mean number of UTI relapses was 0.43 for the treatment group compared with 0.77 for the placebo group (1 side P -value = 0.035). However, a statistically significant difference was not found between the 2 groups in the intent-to-treat population. The number of patients experiencing adverse effects was similar between the groups. Thus, the combination of horseradish and nasturtium may be beneficial in the prophylaxis of UTIs. 19

Clinical data

Research reveals no clinical data regarding the use of horseradish for antibacterial effects.

Other uses

Horseradish peroxidase in combination with the prodrug indole-3-acetic acid has demonstrated cytotoxic activity in vitro toward mammalian cells. 24 Isothiocyanates have demonstrated insecticidal activity. 25


Traditional use for colds and respiratory infections was 20 g/day of fresh or dried root. 1 Some proposed doses include:

Fresh root

2 to 4 g before meals.


In 150 mL of boiled water, steep horseradish 2 g for 5 minutes; administer several times per day.


Fresh juice from 20 g.


Prepare a concentrated product by steeping horseradish root 2 g in 150 mL of boiled water in a covered container for 2 hours. After straining, add 150 g of sugar to 150 mL of liquid to thicken the preparation. 11

Externally, preparations with 2% mustard oil may be used. 2 , 11


Documented adverse effects; avoid use. 3 , 4 , 5 Use should be avoided during pregnancy and lactation because the allylisothiocyanates are toxic mucosal irritants. Horseradish has abortifacient effects.


Anticholinergic drugs, such as atropine, may antagonize the effects of horseradish. Horseradish may enhance the parasympathetic effects of cholinergic drugs, such as bethanecol or pyridostigmine, when given concomitantly. 25

Adverse Reactions

Topical application may cause an erythematous rash or allergic reaction because of the glucosinolate content. 7 Horseradish is part of the cabbage and mustard family, so it may depress thyroid function. The isothiocyanates may irritate mucous membranes upon contact or inhalation.


Despite the potential for severe irritation, horseradish is generally recognized as safe for human consumption as natural seasoning and flavoring. 26 Ingestion of large amounts can cause bloody vomiting and diarrhea. 5


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