Artemisia iwayomogi, a member of the Compositae, is a perennial herb easily found in Korea and used as a traditional medicine to treat liver disease. AIP1, a water-soluble carbohydrate fraction from Artemisia iwayomogi, showed anti-tumor and immuno-modulating activities in animal studies. A subacute toxicological evaluation of AIP1 was performed for 4 weeks in ICR mice. After administration of AIP1 (0, 20, 100, 500 mg/kg/day), the clinical signs, mortalities, body weight changes, hematology, blood clinical biochemistry, urinalysis, organ histopathology, organ weights and gross finding were examined. The results showed that there were no significant differences in body weight changes, food intakes, water consumptions, or organ weights among different dose groups. Also we observed no death and abnormal clinical signs during the experimental period. Between the groups orally treated with AIP1 and the control group, there was no statistical significance in hematological test or serum biochemical values. Histopathological examination showed no abnormal changes in AIP1 groups. These results suggest that no observed adverse effect level (NOAEL) of the oral administration of AIP1 for 4 weeks was considered to be more than 500 mg/kg/day in mice under the condition investigated in current study.