Abstract: Objective To assess the clinical effect of silymarin on cases with nonalcoholic steatohepatitis (NASH). Methods Total of 72 cases with NASH were randomly divided into two groups, the 40 cases of treatment group were treated with silymarin capsules, 70 mg, three times a day, while 32 cases of control group were treated with liver protect tablets, four tablets, three times a day. Both groups were treated for 12 weeks. Differences of serum enzymes, blood fat and abdominal type-B ultrasonic before and after  therapy were tested and the improvement in clinical symptoms were recorded. Results A significant improvement of clinical symptoms, serum enzymes, blood fat and abdominal type-B ultrasonic after treatment were found in both groups (P ＜ 0.05). There were no significant drug adverse reactions. Conclusions Silymarin capsule is effective and safe for improvement of clinical symptoms, and can decrease serum enzymes and blood fat in patients with NASH.