A study on the diuretic action of Siegesbeckiae herba in dogs was made using a clearance technique with ethanol extract. Siegesbeckiae herba ethanol extract (SGEE) administered intravenously in doses 6.0 and 60.0mg/kg elicited diuresis and an increase in sodium and potassium excretion, and it simultaneously produced a decrease in the reabsorption rate of sodium and potassium in renal tubules. Neither renal plasma flow nor glomerular filtration rate changed significantly. SGEE, when infused directly into a renal artery in doses of 0.5 and 1.5mg/kg min, exhibited identical results to the intravenous responses confined only to the infused kidney. The above observations lead to the suggestion that SGEE elicits diuresis in dogs by decreasing the reabsorption rates of sodium and potassium in renal tubles.