Plant-derived ribosome-inactivating protein (RIP) purified from the Chinese medicinal herb tian-hua-fen which is obtained from the root tubers of trichosanthes kirilowii. It has been used as an abortifacient and in the treatment of trophoblastic tumors. GLQ223 (Compound Q), a highly purified form of trichosanthin, has been proposed as antiviral treatment for AIDS.