The present study was conducted to investigate the potential subacute toxicity of AS6, [(3$eta$, 4$alpha$)-3,23-dihydroxyurs-12-en-28-oic acid], by a 4-week repeated oral administration in Sprague-Dawley rats. To test the subacute toxicity, AS6 was administered once daily by gavage to rats at dose levels of 0, 250, 500, and 1000 mg/kg/day for 4 weeks. There were no treatment-related effects on mortality, clinical signs, body weight, food and water consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, necropsy findings, organ weights, and histopathology in any treatment group. In the condition of this study, target organ was not observed and the no-observed-adverse-effect level (NOAEL) was considered to be 1000 mg/kg/day for both male and female rats.