Objective To study the efficacy as well as the mechanism of artificial liver support system (ALSS) in the treatment of hepatitis gravis. Methods Sixty-three patients suffering from hepatitis gravis were treated with ALSS. The liver and renal function and serum endotoxin level were examined before and after ALSS therapy, and the efficacy of ALSS treatment on the different stages and different types of hepatitis gravis were investigated. Results It showed that liver and renal function improved significantly after ALSS therapy. Endotoxin concentration decreased significanHy from (60.27±10.54) ng/L to (28.33±6.57) ng/L( P<0.001), but it increased to (44.18±8.22) ng/L after 3days. The response rates of acute and subacute hepatitis gravis were 100% and 62.5% respectively, and the response rates of chronic hepatitis gravis in early stage, middle stage and late stage were 90.91%、72.22%、39.13% respectively. Conclusions The ALSS is effective in treating hepatitis gravis. The efficacy of ALSS on acute and subacute hepatitis gravis is better than that on chronic hepatitis gravis. It is more suitable to use ALSS in early and middle stage of chronic hepatitis gravis. 