The aim of this experiments was to investigate the effects of Chinese magnolia vine water extract on the renal function, plasma renin activity, plasma levels of aldosterone and atrial natriuretic peptide in rats. The results of this study were as follows; 1. Water balance decreased significantly after administration with Chinese magnolia vine extracts (0.2 ml/200 g of body weight). 2. Urine volume increased significantly after administration with Chinese magnolia vine extracts. 3. Urinary excretion of sodium increased significantly after administration with Chinese magnolia vine extracts. 4. Urinary excretion of creatinine increased significantly after administration with Chinese magnolia vine extracts (0.2 ml/200 g of body weight). 5. Plasma levels of atrial natriuretic peptide decreased significantly after administration with Chinese magnolia vine extracts (0.1 ml/200 g of body weight). 6. Plasma levels of aldosterone decreased significantly after administration with Chinese magnolia vine extracts (0.2 ml/200 g of body weight).