We have made serial metabolic observations in 18 acute episodes of alcoholic ketoacidosis in ten patients. Data from patients treated with only saline initially were compared to data from patients who received modest amounts of intravenous dextrose (7.0 to 7.5 gm/hr). More rapid improvement in the acidotic state was seen in the latter group (P less than .001). The quicker decline in absolute levels and ratio of beta-hydroxybutyrate to acetoacetate when glucose was given suggests that this treatment induced mitochondrial oxidation of the reduced form of nicotinamide adenine dinucleotide (NADH). Since phosphorus is a critical cofactor necessary for NADH oxidation and the glucose-induced correction of the acidosis was associated with a rapid decline in serum phosphorus from an initial mean of 6.79 +/- .82 mg/100 ml SEM to 0.96 +/- 0.12 mg/100 ml in 24 hours, we propose that glucose enhanced the mitochondrial capacity to oxidize NADH by increasing hepatocyte phosphorus. This effect combined with decline in free fatty acid levels results in reversal of acidosis. Our data suggest that glucose provides the safest, most effective treatment for this disorder; addition of either insulin or bicarbonate is usually unnecessary.