BACKGROUND So-ochim-tang-gamibang (SOCG) is a traditional Korean medicine formulated to control internal energy flow (Qi) and has been prescribed to improve stress-induced depressive disorders. OBJECTIVE SOCG has been used in clinical practice for the last two decades and its efficacy against stress-induced thoracic pain has been suggested. Although SOCG has been used as an herbal formula in Korean medicine, its toxicity has not yet been evaluated. In this study, we evaluated the safety of SOCG through a 13-week general toxicity study in rats. METHODS SOCG was administered by oral gavage to rats at doses of 0 (control), 800, 2000, and 5000mg/kg/day over a 13-week period. Toxicity testing was conducted by evaluating mortality, clinical signs, body weight, food consumption, urinalysis, hematology, serum biochemistry, organ weight, necropsy, and histopathology compared with the concurrent control. RESULTS SOCG-related changes were noted in clinical signs and urinalysis. The observed clinical signs were compound-colored stool and salivation. Urinalysis results revealed brown or amber colored urine and elevated levels of protein. However, these changes were not considered to be adverse. CONCLUSIONS The no-observed-adverse-effect-level of SOCG was determined to be above 5000mg/kg in both male and female rats. The result of this study can lay the foundation for the application of SOCG in humans and prove useful for detailed investigations on the toxicity or pharmacological effects of SOCG.