Objective To observe the effect of tiopronin in preventing leukopenia during chemotherapy Methods Tiopronin were used for 0.2gram during chemotherapy. The change of leukocyte was observed after and before chemotherapy.(Results)The level and number of leukopenia in the Tiopronin therapeutic group after chemotherapy was obviously lower than that of control group (P0.05). Conclusions Tiopronin can prevent leukopenia during chemotherapy.