Abstract: Objective To study the effects of Magnesium Isoglycyrrhizinate in the treatment of chronic severe hepatitis B.Methods A total of 100 patients of chronic severe hepatitis B with unusual liver function, increased bilirubin and normal blood pressure were randomly divided into treatment group and control group.Treatment group was given Magnesium 150mg Isoglycyrrhizinate, control group was given 120mg Glycyrrhizin diluted with 250ml of 5% glucose injection (0.9% sodium chloride was used for diabetic patients) intravenously once per day for 4 weeks.Results Results All patients completed 4 weeks of treatment.Alanine aminotransferase (ALT) , γ-glutamyl transferase (GGT) , serum total bilirubin (Tbil) in treatment group were significantly better than that of the control group (P < 0.01) .The improvement of abdominal disten-sion and poor appetite symptoms in the treatment group were obviously better than the control group (P < 0.05) .Conclu-sion Compared with Glycyrrhizin, Magnesium Isoglycyrrhizinate can quickly and effectively relieve fatigue, abdominal distension, poor appetite of chronic severe hepatitis B, and improve liver function.Magnesium Isoglycyrrhizinate can be a good choice in the treatment of patients with chronic severe hepatitis B.