Burdock is a group of plants of the genus Arctium in the family Asteraceae, members of which are used both for food and for herbal medicine. Arctium lappa is a popular ingredient in Japanese cooking (gobo), but also is an ingredient of the herbal treatment for cancer, Essiac, and for various "detoxifying" rememedies.
Also known beggar's buttons, lappa, gobo, burrseed, cocklebur, sticktight, great burdock, thorny burr, love leaves, A. lappa is a biennial herb that "grows up to 1.5 m tall and has large leaves that are dark green on the top and downy gray on the bottom. Flowers are purple and thistle-like with hooked bracts (burrs)." 
Care must be taken not to confuse wild burdock with a poisonous plant it closely resembles, Atropa belladonna or deadly nightshade.
It has, in small studies in rats, protected the liver against a chemical challenge. "The hepatoprotective mechanism of A. lappa could be attributed, at least in part, to its antioxidative activity, which decreases the oxidative stress of hepatocytes, or to other unknown protective mechanism(s)."
Arctiin, a lignan isolated from Arctium lappa (burdock) seeds, in groups of 20 rats, "has a protective effect on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced carcinogenesis particularly in the mammary gland in the promotion period. On the other hand, it may have a weak co-carcinogenic influence on 2-amino-3, 8-dimethylimidazo[4,5-f]quinoxaline (MeIQx)-induced hepatocarcinogenesis. In addition, the results suggested that PhIP is a weak pancreatic carcinogen in female SD rats, targeting acinar cells."
- Jan Schooley - Ginseng and Medicinal Herb Specialist/OMAF (01 January 2003), Japanese Burdock, Ontario Ministry of Agriculture, Food and Rural Affairs
- Lin SC; Lin CH; Lin CC; Lin YH; Chen CF; Chen IC; Wang LY (2002), "(Abstract) Hepatoprotective effects of Arctium lappa Linne on liver injuries induced by chronic ethanol consumption and potentiated by carbon tetrachloride.", J Biomed Sci 9 (5): 401-9
- Hirose M; Yamaguchi T; Lin C; Kimoto N; Futakuchi M; Kono T; Nishibe S; Shirai T (2000), "(Abstract)Effects of arctiin on PhIP-induced mammary, colon and pancreatic carcinogenesis in female Sprague-Dawley rats and MeIQx-induced hepatocarcinogenesis in male F344 rats.", Cancer Lett 155 (1): 79-88