Abstract: OBJECTIVE To study the effect of Yinchen Wuling powder on AQP2 expression and the plasma levels of NO as well as ET-1 in cirrhotic rats with ascites. METHODS The ascites model of cirrhosis was established by intraperitoneal injection of phenobarbital and carbon tetrachloride. The rats were randomly divided into model group, colchicine group, and low, middle and high-dose of Yinchen Wuling powder groups(crude drug 4.3, 8.6, 17.2 g·kg^-1). Ten rats in each group, and ten normal rats were given normal saline as blank group. Serum levels of NO and ET-1 were measured by nitrate reductase method. The expression of mRNA and protein of AQP2 was measured by RT-PCR and Western blotting method respectively. RESULTS Compared with the blank group, the plasma levels of NO and ET-1 in the model group increased significantly(P<0.05). Compared with the model group, the plasma levels of NO and ET-1 in Yinchen Wuling powder treat groups and colchicine group decreased significantly(P<0.05). Compared with the blank group, the expression of mRNA and protein of AQP2 in the liver of the model group were significantly decreased(P<0.05). Compared with the model group, the expression of mRNA and protein of AQP2 in liver of rats in Yinchen Wuling powder treat groups and colchicine group were significantly increased(P<0.05). CONCLUSION The mechanism of Yinchen Wuling powder in treating cirrhotic rats with ascites may be related to reduction of plasma levels of NO as well as ET-1 and the regulation of AQP2 gene expression.