The purpose of this study was to examine the four week repeated toxicity in Sprague-Dawley rats orally administrated with Rhus-II (water fraction of Rhus Veniciflua). In acute toxicity test, three groups (40 rats of both sex) were administrated different dosages of Rhus-II, 2 g/kg (high dosage group), 1 g/kg, 0.5 g/kg and one group (10 rats of both sex) were received by orally only saline according to the Regulation on Korea Food and Drug Administration, respectively. There was no difference in body weight change, feed intake and water consumption among different dose groups. There was no alteration in relative organ weight by the administration of Rhus-II. No death of abnormal clinical signs was observed during the experimental period. Between the groups orally administered Rhus-II and the control group, there was no statistical significance in urinalysis, hematological test or serum biochemical values. There were no gross findings at final sacrifice. There was no evidence of histopathological alteration mediated by four week treatment with Rhus-II. These results suggest that no observable effect level(NOEL) of the test orally administration was considered to be more than 2g/kg in rats under the conditions employed in this study.