Horseradish is a hot, pungent condiment made from a plant in the mustard family. It is most commonly used as a condiment for roast beef, fish, and oysters. Koch's Horseradish is what you might call a horseradish mayonnaise. It is hot and pungent and is the perfect accompaniment for roast beef or lamb. Used like this, horseradish dates back to the 13th century, when Germans and Danes used it as a condiment, stimulant, and digestive medicine. It was later introduced into England in the 16th century, where it is still used to treat hoarseness and coughs. Use it to liven up your next roast beef dinner.