Augmenter of liver regeneration (ALR), produced and released by hepatocytes, has cytoprotective and immunoregulatory effects on liver injury, and has been used in many experimental applications. However, little attention has been paid to the effects of ALR on concanavalin A (Con A)-induced hepatitis. The purpose of this paper is to explore the protective effect of ALR on Con A-induced hepatitis and elucidate potential mechanisms. We found that the ALR pretreatment evidently reduced the amount of ALT and AST in serum. In addition, pro-inflammatory cytokines, chemokines and iNOS were suppressed. ALR pretreatment also decreased CD4(+), CD8(+) T cell infiltration in liver. Besides, we observed that ALR pretreatment was capable of suppressing the activation of several signaling pathways in Con A-induced hepatitis. These findings suggest that ALR can obviously weaken Con A-induced hepatitis and ALR has some certain immune regulation function.