Effect of aspirin and acid on human jejunal mucosa. An ultrastructural study.

To determine the effects of aspirin and hydrochloric acid on human jejunal mucosa, three obese patients with a small intestinal bypass that opened on the abdominal wall as a mucous fistula were studied. An 80-mM solution of HCl, a 40-mM suspension of aspirin (equivalent to two tablets in a glass of water), and a combination suspension of 40 mM aspirin plus 40 mM HCl damaged a mean +/- SE of 26 +/- 13% (P less than 0.05), 24 +/- 5% (P less than 0.05), and 29 +/- 5% (P less than 0.05) of jejunal villi, respectively, 5 min after administration. By 60 min after instillation, considerable recovery had occurred. Scanning electron microscopy revealed focal villous tip erosion and erythrocyte extrusion after all test solutions. In conclusion, aspirin, 40 mM, physiologic concentration of hydrochloric acid, and the combination of acid plus aspirin are each capable of damaging human small intestinal mucosa on direct contact.