Livers from fed male rats were perfused with homologous whole blood and infused with ethanol and insulin. Ethanol raised hepatic glucose output by enhancing gluconeogenesis from perfusate lactate and amino acids. Ketogenesis and the ratio [3-hydroxy butyrate]/[acetoacetate] were also raised. Insulin, infused alone, lowered blood glucose, ketogenesis and total serum amino acids and when added with ethanol opposed the metabolic effects of the latter. Ethanol did not affect serum fatty acids but their concentrations were raised by insulin.