Burdock is a biennial plant found throughout much of Europe, Asia, and North America. There are two main species of burdock: great burdock (Arctium lappa) and common burdock (Arctium minus). The former may grow to as much as 3 meters in height, while the latter species is limited to under 2 meters. The primary characteristic distinguishing the two species is the leaf stalk, which is solid in great burdock but hollow in common burdock. Both species have very large (up to 50 centimeters long) ovate leaves and produce small purple flowers on burr-like heads. The bristled burrs attach readily to clothing or animal fur, contributing to the plant's widespread propagation. Burdock has a very long, thick taproot which contributes to the plant's reputation as a pesky weed. The root of first-year burdock is used for health purposes.
Burdock root contains polysaccharides (including inulin and mucilages), caffeic acid derivatives, polyynes, sesquiterpene lactones, and small amounts of volatile oil of very complex makeup. 5While one study found as many as 14 different polyacetylene compounds in the fresh root, only traces of these were found in the dried root.
Dosage recommendations for burdock root vary widely with intended applications and the form used. Typical recommendations range from 3 to 6 grams of dried whole root (or equivalent preparations) per day. There are no known health hazards of side effects associated with proper administration of burdock root.