Cirsium japonicum DC. (Compositae), distributed in China, Korea, and Japan, is widely used in traditional herbal medicine for the treatment of hemorrhage, hepatitis, hypertension, or circulatory problems. In order to find the bioactive constituents from Cirsium japonicum DC., MTT-guided isolation and identification of the ethanol extracts of Cirsium japonicum DC. have been carried out, and eight compounds were isolated. All of these compounds were isolated for the first time from charred Cirsium japonicum DC., and compounds 4 and 6 were obtained from the genus Cirsium for the first time.