Abstract: Some pharmacological actions of acetylstrophanthidin were studied as follows: (1) The effect of the drug was very rapid; full effectiveness was reached within 20minutes after the intravenous injection and the toxic effect weared off in less than 14 minutes. This confirmed that acetylstrophanthidin may be employed as digitalis tolerance test. (2) The cardiotoxic effect of acetylstrophanthidin is obvious. The appearance of multifocal ventricular premature contractions and short runs of ventricular tachycardia were the most frequently encountered toxic effects. Other side effects were sinus arrest, ventricular rhythm, atrioventricular dissociation, and first degree atrioventricular block.The most serious toxic effect was ventricular fibrillation. (3) The combined use of acetylstrophanthidin and ouabaine was proved to have accumulative effect. (4) Prior to the deaths, all animals had serious arrhythmias. Overdosage is the main factor responsible for deaths.