Nardostachys jatamansi is a medically important herb of Indian origin used for centuries in Ayurvedic and Unani systems of medicine for the treatment of various ailments. In the present paper, a 50% ethanolic extract of the rhizomes of N. jatamansi is shown to possess hepatoprotective activity. Pretreatment of rats with the extract (800 mg/kg body wt, orally) for three consecutive days significantly ameliorated the liver damage in rats exposed to the hepatotoxic compound thioacetamide. Elevated levels of serum transaminases (aminotransferases) and alkaline phosphatase, observed in thioacetamide alone treated group of animals, were significantly lowered in N. jatamansi pretreated rats. Pretreatment of the animals with the extract also resulted in an increase in survival in rats intoxicated with LD90 dose of the hepatotoxic drug.