Background: Lipid peroxidation is thought to play a role in the evolution of liver damage, based on evidence in experimental models, However, evidence that lipid peroxidation occurs in patients with liver disease remains to be provided. We addressed the hypothesis by measuring levels of 8-epi Prostaglandin F-2 alpha a bioactive prostaglandin isomer produced by free radical catalyzed peroxidation of arachidonic acid, in patients with liver cirrhosis. Methods: In 42 patients with hepatic cirrhosis 8-epi Prostaglandin F-2 alpha, factor VII activity, endotoxemia, carotenoids and alpha-tocopherol were measured. In 10 patients 8-epi Prostaglandin F-2 alpha was also measured before and 30 days after 300 mg b.i.d. vitamin E administration. Results: Cirrhotic patients had significantly higher 8-epi Prostaglandin F-2 alpha, excretion than controls [median (range): 199.2 (60.0-812) vs 85.9 (55.6-160.0) pg/mg creatinine, p