The plasma concentrations of salicylate and indomethacin were measured after a single oral dose of aspirin (600 mg) and indomethacin (50 mg) in twelve starved normal subjects and twelve adult patients with coeliac disease. The absorption of salicylate in the coeliac patients was faster than in the normal subjects. The plasma concentration/time curve of indomethacin in both groups was similar during the absorption phase, but there were significant differences between the groups in its elimination. The abnormal absorption pattern of salicylate in coeliac disease does not appear to be related to its pKa. Possible causes of the difference in salicylate absorption include changes in gastric emptying or altered small intestinal permeability.