The anti-inflammatory activity of Cassia occidentalis leaf powder and an ethanol extract of Cardiospermum halicacabum aerial parts were assayed in male albino rats using carrageenan-induced rat paw edema. C. occidentalis was maximally active at a dose of 2000 mg/kg, while the C. halicacabum extract was maximally effective at a dose of 500 mg/kg. In the cotton pellet granuloma assay, these drugs were able to suppress the transudative, exudative and proliferative components of chronic inflammation. Further, these drugs were able to lower the lipid peroxide content and gamma-glutamyl transpeptidase and phospholipase A2 activity in the exudate of cotton pellet granuloma. The increased alkaline phosphatase activity and decreased A/G ratio of plasma in cotton pellet granulomatous rats were normalized after treatment with these drugs. C. occidentalis powder and C. halicacabum extract were able to stabilize the human erythrocyte membrane against hypotonicity-induced lysis. It is likely that these drugs may exert their anti-inflammatory activity by inhibition of phospholipase A2, resulting in the reduced availability of arachidonic acid, a precursor of prostaglandin biosynthesis, and/or by stabilization of the lysosomal membrane system.