The present study was carried out to investigate the hepatoprotective effect of two doses of the extract of Ptercarpus santalinus Linn. on acute hepatotoxicity induced in Wistar albino rats by a single dose of D-galactosamine (400 mg/kg) . Suspensions of methanolic extract of heartwood of Pterocapus santalinus (200 mg/kg and 400 mg/kg) in 0.3% carboxy methyl cellulose (CMC) were administered p.o. to experimental animals according to the protocol followed by the i.p. administration of a single dose of hepatotoxin. Hepatoprotective activity was monitored by estimating aspartate amino transferase (ASAT, GOT), alanine amino transferase (ALAT, GPT), total bilirubin (TB), lactate dehydrogenase (LDG), total cholesterol (TC), triglycerides (TGL), albumin, total protein (TP) levels and histopathological changes in the livers of P. santalinus - treated groups of animals. The results clearly indicated that the extract of P. santalinus significantly reduced the acute elevation of serum transaminases and alteration of other biochemical parameters induced by hepatotoxin, and alleviated the degree of liver damage at 24 hrs. after the intraperitoneal administration of the hepatotoxins. Silymarin (25 mg/kg), a known hepatoprotective drug was used for comparison. The results were supported by histopathological studies of liver samples showing regeneration of hepatocytes in treated animals. Based on the results obtained in the present investigation, it can be concluded that Pterocarpus santalinus exerts hepatoprotective activity and may serve as a useful adjuvant in severl clinical conditions associated with liver damage. (Author's abstract)