The purpose of this research was to investigate cytotoxicity of DangkwiYonghoe-Hwan(DYH) and the constitutive crude drugs on several cancer cell-lines, thymocytes, splenocytes and 3T3 cells. The DYH consists of Coptidis Rhizoma, Scutellariae Radix, Phellodendri Cortex, Gardeniae Fructus, Gentianae scabrae Radix, Indigo pulverata Levis, Aloe, Rhei Rhizoma, Moschus, Saussureae Radix and Angelicae Gigantis Radix. The cytotoxicity was determined by MTT method. The DYH inhibited the proliferation of MOLT-4, K562, HL-60, Jurkat, L1210, P815, S180 and Yac-1, thymocyte, splenocyte and 3T3 cells. The cytotoxicity of Coptidis Rhizoma on the cancer cell-lines was the most potent in the constitutive crude drugs. The proliferation of cancer cell-lines was partly inhibition and partly increase by the treatment of Scutellariae Radix, Gardeniae Fructus, Gentianae scabrae Radix, Indigo pulverata Levis, Aloe, Rhei Rhizoma, Moschus and Angelicae Gigantis Radix. Phellodendri Cortex and Saussureae Radix had a poor cytotoxicity on cancer cell-lines. Coptidis Rhizoma and Phellodendri Cortex inhibited the proliferation of thymocyte, splenocyte and 3T3 cells.