It has been reported that bimolane can inhibit either humoral or cell-mediated immunological responses in vivo in mice & the inhibition of humoral immunity (by bimolane) is stronger than that of cellular immunity. Author investigated the influence of bimolane on the mitogen-induced mouse lymphocyte proliferation. Bimolane inhibited the lymphocyte proliferation induced by Con A(concana-valin A), PHA ( phy tohemagglutinin ) or LPS(lipopoiysaccharide) . Bimolane dose-dependently inhibited LPS-induced lymphocyte proliferation with remarkable inhibition at 1.56 mg/L bimolane. The inhibition of Con A-induced or PHA-induced lymphocyte proliferation by bimolane, however, began to appear at above 6.25 mg/L bimolane. The bimolane-mediated inhibition of the proliferation of the lymphocytes was not due to a nonspecific toxicity, because the preincubation of spleen cells with 25 mg/L bimolane for 24h did not make the cells died tested by trypanblau exclusion method.The data suggest that B lymphocytes are more sensitive to the bimolane-mediated inhibition than T lymphocytes.