The lipid peroxidation inhibitor U74006F (21-[4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl-16-methylp regna- 1,4,9 (11)-triene-3, 20-dione) was tested for cerebroprotective properties in the rat. Transient forebrain ischemia was induced by occlusion of the carotid arteries and simultaneous lowering of the blood pressure to 40 mmHg. Repetitive doses of 10 mg/kg U74006F were administered intraperitoneally 10 min before and again 30 min and 24 h after the transient forebrain ischemia. U74006F did not significantly improve histological outcome in this model, suggesting lipid peroxidation to be a minor determinant for the neurological outcome under these experimental conditions.