Aspirin-induced gastric bleeding stops despite rising plasma salicylate.

In 7 subjects, 100-ml successive portions of buffered acid (pH between 3.5 and 2.9) solutions of aspirin (1 g/liter) were instilled into the stomach and recovered after 10 min. Blood in the recoveries was estimated chemically. After there had been three successive increases in the rate of blood loss into the gastric lumen, typically rising from about 0.1 to 1 ml/day after about 80 min, buffered neutral solution of aspirin was instilled and recovered after 10 min. This was followed by a fall in the rate of blood loss into the gastric lumen which occurred despite a rise in the concentration of salicylate in the plasma from a mean of 55 mg/liter to 74 mg/liter. Under these conditions, salicylate in the plasma and acetylsalicylate in the gastric contents did not prevent gastric mucosal bleeding from falling to control levels within 50 min.