Objective: To investigate the direct protective effect of SiniTang (SNT) on cultured myocardial cells of neonatal rats injuried by hypoxia and reoxygenation. Methods: The contracting frequency and content of primary-cultured myocardial cells sampled from different groups (control, oxygen and glucose deprivation model, and theated groups with 8. 0, 17. 9, 40, 89. 4, 200?g/mL SNT) were determined by TV recording system and computer image analysis system at different time (hypoxia for 30min, 60min, 90min, 120min, 150min, 180min and reoxygenation for 30min, 60min). The LDH activity in culture media was measured colorimetrically. The quantity of surviving myocardial cells was measured with MTT reduction method. Results: The contraction frequency and range of cultured myocardial cells decreased during hypoxia, the myocardial cells'pulsation of the groups treated with SNT was kept longer than the oxygen and glucose deprivation model, and the myocardial cells treated with SNT of 200?g/mL pulsed again after reoxygenation. After hypoxia for 3 hours, the LDH release of oxygen and glucose deprivation model was significant higher than that of the control ( P