Cianidanol is an antioxidant flavonoid, occurring especially in woody plants as both (+)-catechin and (-)-epicatechin (cis) forms. One of the polyphenols present in green tea, (+)-catechin (Cianidanol), has been studied for its effects on animal models of hepatitis, as well as in human clinical studies. Pure (+)-catechin (also known as (+)- cyanidanol-3 – trade name Catergen) has been used to treat hepatitis since 1976. This compound has been shown to be an efficient immune stimulator, promoting activation of macrophages, cytotoxic-T-lymphocytes, and natural killer cells in mice. Several clinical studies demonstrate the effectiveness of (+)-catechin in the treatment of viral hepatitis. Pure (+)-catechin has been found to cause hemolysis in some patients, possibly by the promotion of antibody formation against (+)-catechin, which might cross-react with red blood cells. However, there are no reports in the literature of green tea, green tea extracts, or green tea polyphenols causing this side-effect.