Severe acute hepatitis of unknown etiology is difficult to treat and often progresses to subacute fulminant hepatitis or late-onset hepatic failure. A 45-year-old wellnourished, healthy man had progressive fatigue and his liver function tests showed severe liver dysfunction. The etiology of sever acute cholestatic hepatitis was unknown. The liver function tests normalized gradually, which excluded high persistent total bilirubin after starting on predonine. A liver biopsy showed chronic active hepatitis with mild f ibrosis (A2, F1). Oral Inchinko-to, a Chinese herbal medicine, at 7.5 g daily was prescribed. The treatment was effective with no adverse effects. We present a successfully treated case and discuss hepatoprotective and choleretic effects of Inchinko-to. Severe acute hepatitis of unknown etiology is difficult to treat and often progresses to subacute fulminant hepatitis or late-onset hepatic failure. A 45-year-old wellnishedished, healthy man had progressive fatigue and his liver function tests showed severe liver dysfunction. The etiology of A liver biopsy showed chronic active hepatitis with mild f ibrosis (A2, F1). Oral Inchinko-to, a Chinese herbal medicine, at 7.5 g daily was prescribed. The treatment was effective with no adverse effects. We present a successfully treated case and discuss hepatoprotective and choleretic effects of Inchinko-to.