Seventy five medicinal plants of the traditional Ayurvedic pharmacopoeia of Sri Lanka have been screened chemically for alkaloids and pyrrolizidine alkaloids. Of these, Crotolaria juncea L. was found to contain pyrrolizidine alkaloids with biological effects consistent with pyrrolizidine alkaloid toxicity. Feeding trials in rats with three plants lacking pyrrolizidine alkaloids, namely Aegle marmelos (L.) Corr., Hemidesmus indicus (L.) Ait. F. and Terminalia chebula Retz. produced hepatic lesions which included central vein abnormalities while Terminalia chebula and Withania somnifera (L.) dunal produced marked renal lesions.