The chemical content of Turkish Castanea sativa propolis is investigated, along with its protective effect against alcohol-induced oxidative stress. The ethanol-propolis extract, at dose of 200 mg/kg body weight/day, was given, by gavage, to male rats for 15 days. At the end of the treatment, serum lipid levels, activities of liver enzymes and other biochemical parameters were measured. HDL level decreased and LDL level increased in the alcohol group, while HDL level increased and LDL level decreased in the alcohol + propolis group. There were decreases in cholesterol and triglyceride levels in the alcohol + propolis group. Also, there were decreases in ALP and AST enzyme activities, but LDH enzyme activity increased in the propolis treatment group compared to the alcohol group. No toxic effects of Turkish C. sativa propolis were found, while it caused an increase in HDL level and a decrease in LDL level. We suggest that these effects are protective against degenerative diseases and against alcohol-induced oxidative stress via free radicals. (C) 2002 Elsevier Science Ltd. All rights reserved.