AbstractSeveral studies have suggested that muscle lactic acid production is defective in alcoholic myopathy. However, normal controls have not been evaluated. To study the effects of ethanol on the production of lactic acid in normal exercised muscle, oral ethanol (1 g per kg body weight, 20% v/v) was given to eight nonalcoholic subjects. Forearm ischemic exercise with a total work load of 7.2 kg‐m/min was performed just before and 90 min after ingestion of ethanol. At the time of exercise, the serum ethanol level was 95.7 ± 15.1 mg% (mean ± SD). Resting serum lactic acid was significantly higher after ingestion of ethanol (15.7 ± 4.5 mg%) than before (8.5 ± 4.7 mg%). Lactic acid generation with ischemic exercise was significantly lower after ethanol ingestion. The mean peak serum lactic acid level (expressed as percentage elevation above resting) was 330.5 ± 118.2% before and 127.9 ± 75.1% after (p<.05). These results indicate that a single oral dose of ethanol decreases lactic acid production by exercised muscle in normal s