The next time you have a couple of drinks and think about throwing down a preventive aspirin or two, consider that research has determined this might elevate your blood-alcohol level above the legal limit:

Aspirin increases blood alcohol concentrations in
humans after ingestion of ethanol

Gastric first-pass metabolism of ethanol is an important determinant of blood alcohol concentrations. We studied five healthy volunteers after ingestion of ethanol (0.3 g/kg of body weight) and found that blood alcohol concentrations in the fed state (ie, 1 hour after a standard breakfast) were significantly higher when the subjects received 1 g of aspirin 1 hour before ingestion of ethanol than without the drug. In vitro, aspirin clearly decreased the activity of gastric alcohol dehydrogenase in human subjects…Thus, aspirin may increase the bioavailability of ingested ethanol in humans, possibly by reducing ethanol oxidation by gastric alcohol dehydrogenase.

(Thanks to Chuck Laroue.)