The spicy root of the horseradish plant is a widely used condiment. Native to southeast Europe, it is currently widely cultivated in Germany. In Japan, it is called wasabi, and forms a ubiquitous part of sushi cuisine.
Horseradish root also has a long history of medicinal use. Taken internally, it was thought to be effective for bladder infections as well as other bladder and kidney problems. (Horseradish oil once formed a part of a drug licensed in the US for treatment of bladder infection; however, contrary to statements made on some websites, this drug is no longer in use.) Horseradish was also taken internally as a treatment for respiratory infections and for joint pain. It was also applied externally in the form of a poultice to wounds, painful joints, and strained muscles.
There are no scientific studies of horseradish that have attained even the minimum level of scientific reliability. Only double-blind, placebo-controlled studies can show a treatment effective, and no such studies of horseradish taken by itself have yet been reported. (For information on why such studies are essential, see Why Does This Database Rely on Double-Blind Studies?)
Germany’s Commission E has approved horseradish for supportive treatment of urinary tract infections as well as for treatment of respiratory infections such as acute bronchitis, colds, sore throat, and sinusitis; however, this approval is more on the base of tradition than science.
Test tube studies performed in the 1950s indicated that horseradish essential oil has antimicrobial properties.1 However, it is a very long way from test tube studies to actual efficacy in people; virtually all essential oils have antimicrobial properties in the test tube, but none have gone on to show value as antibiotics.
Constituents of horseradish essential oil include the substance families glucosinolate, gluconasturtiin, and sinigrin. These and similar substances are also found in the plant nasturtium. A preliminary double-blind, placebo-controlled study published in 2007 found some evidence that a standardized combination of nasturtium and horseradish might prevent new bladder infections among people with a history of recurrent bladder infections.2 This study, however, suffered from numerous problems in design and statistical analysis. An even less reliable human trial found weak evidence that this combination could be helpful for children with sinusitis, bronchitis, or urinary tract infections.3
A typical recommended dose of horseradish is 3 to 5 g of the freshly grated root taken three times daily, or 2 to 3 ml daily of horseradish tincture. For external use, freshly grated root is wrapped in thin gauze and applied to the skin until a sensation of warmth develops. The combined nasturtium-horseradish product mentioned above should be taken according to label instructions.
As a commonly consumed condiment, horseradish is believed to be relatively safe. However, because of its spicy nature, it can cause burning mouth pain, sweating, and gastrointestinal distress. Left too long in contact in the skin, marked irritation may develop. It is definitely not advisable to get horseradish products in contact with the eyes.
Maximum safe doses of horseradish have not been established for pregnant or nursing women, young children, or people with serious liver or kidney disease.
1. Kienholz M. Studies of antibacterial substances from horseradish ( Cochlearia armoracia), nasturtium ( Tropaeolum maius) and garden peppergrass ( Lepidium sativum). Arch Hyg Bakteriol. 1957;141:182-197.
2. Albrecht U, Goos KH, Schneider B. A randomised, double-blind, placebo-controlled trial of a herbal medicinal product containing Tropaeoli majoris herba (Nasturtium) and Armoraciae rusticanae radix (Horseradish) for the prophylactic treatment of patients with chronically recurrent lower urinary tract infections. Curr Med Res Opin. 2007 Aug 24. [Epub ahead of print]
3. Goos KH, Albrecht U, Schneider B. On-going investigations on efficacy and safety profile of a herbal drug containing nasturtium herb and horseradish root in acute sinusitis, acute bronchitis and acute urinary tract infection in children in comparison with other antibiotic treatments]. Arzneimittelforschung. 2007;57:238-246.
Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 12/15/2015