So is bayer aspirin good to take after a night of drinking?

Not necessarily: Victor, aspirin may help with the headache of a hangover, but it and alcohol can both increase risk of gastritis and intestinal bleeding. Use with caution. Hope this helps.

Not so safe: Aspirin does cause gastritis(Inflammation and even ulceration in the lining of the stomach). Alcohol has similar but milder effect on the stomach lining. So two of them together can create a bleeding ulcer and hence not recommended to be taken together. Aspirin does relieve the Headache of the hang over from alcohol but a safer medicine would be the use of Tylenol (acetaminophen) instead of aspirin.