The effects of wuweizisu C, a lignan component of schizandra fruits, on liver injuries induced by carbon tetrachloride (CCl4), d-galactosamine and dl-ethionine were investigated by means of serum-biochemical and histopathological examinations in rats. Pretreatment or combined administration of wuweizisu C dose-dependently reduced the elevation of serum transaminase activity and histological changes such as fatty degeneration, cell necrosis, inflammatory cell infiltration, etc., which were caused by the single administration of 1 ml/kg, p.o., or the repeated administration of 0.2 ml/kg, s.c., daily for 4 days of CCl4, respectively. The effects of wuweizisu C on the liver injuries induced by a low dose (200 mg/kg, i.p.) and a high dose (400 mg/kg, i.p.) of d-galactosamine were compared with those of uridine. Wuweizisu C significantly lowered the rise of serum transaminase activity after the administration of a low dose of d-galactosamine in the serum-biochemical analysis. A tendency was also shown to inhibit cell necrosis and inflammatory cell infiltration caused by both doses of d-galactosamine in the histopathological examination. On the other hand, uridine markedly repaired the serum-biochemical and histopathological changes after the administrations of both doses of d-galactosamine. Also wuweizisu C cured the liver injury by the repeated administration of 150 mg/kg, i.p., daily for 4 days of d-galactosamine. After the repeated administration of 250 mg/kg, s.c., daily for 4 days of ethionine, liver cell atrophy, diffuse fatty degeneration and decrease of serum triglyceride were observed, but not cell necrosis. Wuweizisu C dose-dependently inhibited fatty degeneration and decrease of serum triglyceride. These findings suggest that wuweizisu C can be protective and/or therapeutic on hepatocellular phenomena such as cell necrosis, fatty degeneration, inflammatory cell infiltration, etc., in human hepatitis.