Chaga (the sclerotia of Inonotus obliquus) has been widely used as a folk medicine in the treatment of cancer, cardiovascular disease and diabetes in Russia, Poland, and several Baltic countries. More recently, this herb has been assessed for its cancer-preventing activity. Using a mouse model of skin cancer, oral administration of Chaga was found to inhibit tumor promotion by 12-O-tetradecanoylphorbol-13-acetate following initiation with 7,12-dimethylbenz[a]anthracene in mouse skin.