The present study has been undertaken to evaluate renal and hepatic toxicity of the extracts of Calotropis gigantea Linn. Animals were divided into various control and experimental groups. Crude and ethanolic extracts were prepared and 150 and 300 mg/kg body weight doses were selected. At lower dose of 150 mg/kg body weight the toxicity was not so much pronounced whereas at 300 mg/kg body weight both extracts were found to be highly toxic. They produced hypertrophy of liver cells together with their nuclear degeneration and hyperchromasis. These changes can be due to improper carbohydrate metabolism. Kupffer cell population increased considerably. There was disruption of tunica intima of central vein. Tubular necrosis, loss of epithelium and shrinkage of glomeruli are commom degenerative changes in the kidney at 300 mg/kg body weight dose.