Five species of crude drugs are used as "Thang-kau-tin" on Taiwan market: (1) the stem of Mallotus repandus (Willd.) Muell.-Arg, (2) the stem and root of M. repandus (Willd.) Muell.-Arg, (3) the stem of Bauhinia championii Benth, (4) the stem with hooks of Uncaria hirsuta Haviland and (5) the stem