Test meals of 200 ml containing acetylsalicylic acid or buffered acetylsalicylate were given to 19 healthy subjects. Studies were made of the rate of gastric emptying and the gastric absorption of acetylsalicylic acid. It was found that the buffered acetylsalicylate test meals (pH 7.0) were emptied more rapidly from the stomach than test meals containing unbuffered (pH 2.8) acetylsalicylic acid. After 10 min, considering the means of amounts of aspirin absorbed, there was at least 10 times less absorbed from the buffered solution. No bleeding into the gastric contents was observed in response to any test meal.