This study was carried out to investigate the protective effects of curcumin on acute or subacute carbon tetrachloride-induced liver damage in rats. Acute hepatotoxicity was induced by intraperitoneal injection of carbon tetrachloride after 4 consecutive days of curcumin treatment. Subacute hepatotoxicity was induced by oral administration of carbon tetrachloride twice a week during 4 weeks of curcumin treatment. In rats with acute liver injury, curcumin (100 and 200 mg kg(-1)) lowered the activity of serum alanine aminotransferase to 52-53% (P < 0.05) and aspartate aminotransferase to about 62% (P < 0.05) those of control rats. In rats with subacute liver injury, curcumin (100 mg kg(-1)) lowered the activity of serum alanine aminotransferase to 34% (P < 0.01) and alkaline phosphatase to 53% (P < 0.05) of control rats. The liver hydroxyproline content in the curcumin (100 mg kg(-1))-treated group was reduced to 48% of the carbon tetrachloride control group (P < 0.01). Malondialdehyde levels in curcumin (100 mg kg(-1)) treated rat liver was decreased to 67% of the control rat liver (P < 0.01) in subacute injury. It was concluded that curcumin improved both acute and subacute liver injury induced by carbon tetrachloride in rats.