This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Burdock Root, Arctium Lappa. Official in Austria. Has been deleted from the U. S. P. IX. Contains inulin and a bitter principle. Burdock is diuretic and alterative. It is one of the Compositae, several of which have a reputation as alteratives, though few are toxic. The Compositae should be given scientific investigation. Burdock, for instance, has no scientific status, yet it is empirically used and highly esteemed by many physicians. In my own hands it has served quite well as a diuretic alterative in the treatment of chronic skin diseases and the nebulous class of chronic troubles commonly, but erroneously, termed "Chronic rheumatism." Give the fl. in 5- to 30-minim doses for a considerable period of time, and results will probably justify the effort; but don't expect too much of burdock.