Phytolaccae Radix (PR), Brunella Herba (BH), Akebiae Lignum (AL) and Atractylis Rhizoma (AR) are some of the diuretic agents used in Chinese medicine and folk remedy. Water or methanol extracts of them (100mg/kg) were intravenously injected to rabbits in order to re-evaluate the effects on renal function. PR water extract elicited moderate diuresis while water extracts of BH, AL and methanol extract of AR had antidiuretic effects. Influence of PR on renal hemodynamics and Na⁺-K⁺-ATPase activity in rabbit kidney were observed in vivo and in vitro. The results were as follows: 1) Clearances of inulin and p-aminohippuric acid increased significantly after 15 minutes following the administration of PR water extract, but Na+ reabsorption rate was not changed. 2) The increase of Na⁺-K⁺-ATPase activity in renal cortex, outer and inner medulla was observed at 15 minutes after PR water fraction was given intravenously, and the change was most prominent in cortical area. 3) More than 50% of decrease in Na⁺-K⁺-ATPase activity in renal tissues was observed with PR water fraction (10^-2g/ml) in vitro experiments. However, the inhibition of Na⁺-K⁺-ATPase activity was reversed with lower concentrations (10^-4g/ml, 10^-6g/ml) of PR water fraction in outer and inner medullary zone. These results suggest the diuretic effect of PR is due to improved renal hemodynamics, and contradictory reults concerning Na⁺-K⁺-ATPase activity require further investigation.