Horseradish has a long history of use in veterinary medicine. The tangy horseradish root's benefits on equine well-being have experienced a revival in recent years.
What does horseradish plant look like and where does it grow?
Horseradish (Armoracia rusticana) grows all over Europe and western Asia. This herbaceous plant is from the family Brassicaceae. It grows wild in damp meadows and embankments and can grow to 2 metres in height. The large, wavy, lanceolate leaves grow upright in rosette clusters up to one metre long. Crushing the leaves will release the unmistakable pungent smell which distinguishes it from similar-looking docks and sorrels. From May until July, the horseradish plant puts out fragrant white blossoms in bunches which sprout from the leaf axils and mature into small, round seed pods. The strong root stock is made up of thick, fleshy tapered roots that grow to 60 cm straight down into the earth, allowing the plant to survive at temperatures to minus 50 °C. Horseradish has been cultivated as a vegetable, a spice, and a medicinal plant since the Middle Ages because of these pungent roots.
The name "horseradish" is somewhat misleading because it is not closely related to the various piquant radishes of the genus Raphanus. The true origin of the plant's name remains a bit unclear – the word horse was formerly used to denote large size and coarseness. At the same time, horseradish has a long history as a medicinal plant for horses.
Which part of the horseradish plant is used?
Phytotherapy as well as cookery primarily make use of the large roots. However, the lateral roots and the young shoots are also edible.
The 4 to 6 cm thick horseradish root is brown on the outside and white inside. It is harvested mainly in autumn, when its nutrients and pungency are at their peak. When cut, the root produces the substance that gives the plant its tell-tale odour and taste, resulting in watery eyes and a runny nose. Eating too much raw horseradish will make your throat burn, and then only inhaling the scent of a slice of bread will help. Cooking will diminish the pungency, as will lengthy storage times.
What makes horseradish so pungent?
The root contains glucosinolates, also called mustard oil glycosides. These are secondary plant substances that are broken down by grating, chopping, or chewing and are split by enzymes into mustard oils. When released, mustard oils irritate the mucous membranes.
What benefits do the substances in horseradish bring?
Horseradish root contains lots of vitamin C, vitamin B, and minerals like iron, magnesium, calcium, potassium, and phosphorus. The root is also high in secondary plant substances with antioxidant properties that boost the immune system. However, the most important substances in horseradish are its pungent mustard oils and essential oils with their mucolytic and antimicrobial effects. Horseradish's effectiveness against bacteria such as E. coli was confirmed in the 1950s, earning it the name "garden penicillin". Its volatile and oily active substances also help to curb viral and fungal infections.
After ingestion of horseradish, the degradation products of the mustard oils are exhaled through the lungs and eliminated through the urinary tract.
What equine ailments can horseradish be used to treat?
Horseradish is traditionally used to treat bronchitis, upper respiratory infections, and bladder inflammations. Its pungent substances ensure good blood circulation in the mucous membranes and stimulate glandular activity.
Horseradish's beneficial effects on metabolism and the immune system and its effectiveness against germs from the environment allow it to lend optimum support to the horse's general well-being, for example in stressful situations and during deworming treatment.
Most horses have no problem ingesting horseradish preparations mixed in with their feed.
Caution: To avoid stomach irritations, divide daily doses of horseradish into several portions! Follow the manufacturers' recommendations when feeding your horse ready-made products!
Horseradish can also be applied externally in the form of poultices to increase blood circulation in the skin and generate heat, as well as activate the healing process in cases of osteoarthritis, windgalls, and swollen legs.
Caution: Horseradish can cause severe skin irritations in some horses. Do not apply horseradish externally if your horse shows a sensitivity to it!
Sources and further reading
Brendieck-Worm, C., & Melzig, M. F. (2018). Phytotherapie in der Tiermedizin. Stuttgart: Georg Thieme Verlag KG.
Reichling, J., Gachnian-Mirtscheva, R., Frater-Schröder, M., Di Carlo, A., & Widmaier, W. (2008). Heilpflanzenkunde für die Veterinärpraxis. Berlin-Heidelberg: Springer Medizin Verlag.