Mustard is a medicinal plant from the Cruciferae family with several botanical names. It is commonly known as mustard, black mustard, white mustard, and yellow mustard. The plant grows throughout Europe except the northeast, as well as parts of Asia and Africa. It is an erect annual plant that can grow over 3 feet tall with small flowers and spear-shaped leaves. The seeds are used both as a spice and in medicine, where the rubefacient properties cause mild skin irritation to stimulate circulation and relieve muscle and bone pain.