Rheum officinale is a rhubarb from the family Polygonaceae originating in Asia. Herbs large, 1.5-2 m tall. Rhizomes and roots stout. Stem stout, hollow, finely sulcate, with white hairs, especially above and at nodes. The root and stem of R. officinale are used to treat constipation, as well as to aid in the dissolution of blood clots and pus eruptions. Is used in traditional Chinese medicine, where it is called yao yong da huang, and is also a component in the North American herbal remedy called Essiac tea. In modern medicine, R. officinale has been found to be useful in treatment of Hepatitis B. Anthranoids, especially anthraquinone glycosides: rhein (sennosides A and B), aloe-emodin, physcion. Oxalic acid. Tannins (5% - 10%): gallotannin, catechin, procyanidin. Other: pectin, phenolic carboxylic acids. Pectin tends to be antidiarrheal. In conjunction with tannins, its effect may supersede the effect of anthraquinones when rhubarb is given is small doses.