Cardiotoxic effects of adriamycin were investigated in cultured heart cells. Three-day cultured myocardial cells were treated with the different doses of adriamycin (0.3mg/L, 1 mg/L, 3 mg/L) , and incubated in verieus times times ( 4 h, 8 h, 24h ) , and, then the content of lactate dehydrogenase ( LDH ) in media and malondialdehyde ( MDA ) in cells were measured. The results showed that the content of LDH in media increased with the time in culture. The content of LDH in media and MDA in cells increased markedly with the increase in adriamycin concentration. It suggested that the adriamycin has direct damage to myocardial cells, which is time-dependent and dose-dependent.