Burdock (Arctium lappa) is a plant native to Japan that is now found all over the world. The root is eaten as food. The root, leaf, and seed are used as medicine. Burdock contains chemicals that might help fight bacteria and swelling. In traditional Chinese medicine, it’s used to get rid of toxins and as a “blood purifier.” People use burdock for aging skin, stomach problems, joint swelling, and many other conditions, but there is no good scientific evidence to support its use.