This study was designed to observe the effects of the Schizandra chinensis Baillon water extract (SCB) on the improvement of the blood glucose level of streptozotocin (STZ)-induced insulin dependent diabetic rats for 4 weeks. Experimental groups were assigned to normal control group (Normal), diabetic control group (STZ) and diabetic group treated with Schizandra chinensis Baillon water extract (100, 500, 1,000 ㎎/㎏; SCB100, SCB500, and SCB1000, respectively). The changes of body weight were significantly increased with adding the Schizandra chinensis Baillon water extract compared to STZ control group. Food intakes of SCB500 and SCB1000 showed significant reduction of 31.9% and 29.8% compared to STZ control group (48.6 ± 3.1 g/day). Food efficiency ratio of SCB500 and SCB1000 were increased more than one and half times as compared to STZ control group. Water consumptions of SCB100 and SCB500 treated groups were significantly decreased to that of STZ control group. Blood glucose levels of all SCB treated groups were significantly decreased to 26.5, 40.5 and 46.5% compared to those of STZ control group at 4 weeks. Serum insulin levels of all SCB treated groups were significantly increased compared to those of STZ control group at 2, 3 and 4 weeks. These results suggested that Schizandra chinensis Baillon water extract improve STZ-induced insulin dependent diabetic symptoms such as hyperglycemia, hypoinsulinemia, polyphagia and polydipsia in rats.