The effects of an ethanol extract of the plant Sophora flavescens Ait. on haemodynamics and ventricular fibrillation threshold were studied in pentobarbitone-anesthetized dogs. It was found that intravenous injection of the extract, 120 mg/kg, caused transient but significant depression in systolic and diastolic blood pressure, heart rate, left ventricular pressure and dL VP/dtmax, as well as elevation of ventricular fibrillation threshold. These preliminary findings suggest that the ethanal extract of Sophora flavescens Ait. possess pharmacological activites resembling those of antiarrhythmic agents, but the mechanisms of action are unclear.