Horseradish is a perennial plant of the Brassicaceae family(which also includes mustard, wasabi, broccoli, and cabbage). The plant is probably native to southeastern Europe and western Asia. Horseradish is now popular around the world. It grows up to 1.5 meters (4.9 feet) tall and is cultivated primarily for its large, white, tapered root.The intact horseradish root has hardly any aroma. When cut or grated, however, enzymes from the now-broken plant cells break down sinigrin (a glucosinolate) to produce allyl isothiocyanate (mustard oil), which irritates the mucous membranes of the sinuses and eyes.