The pH and transit times of the gut are important for the delivery of active drug from several tablets used in the treatment of Crohn's disease (CD). Many patients with CD undergo an ileocecal resection, which might influence small intestinal pH and transit time. The effect of ileocecal resection on these variables has not previously been studied. Intraluminal pH and transit time were measured in nine ileocecal-resected CD patients and 13 healthy volunteers using pH-sensitive radiocapsules. Small intestinal transit time (SITT) was significantly shorter in ileocecal-resected patients (5.2 hr, controls 8.0 hr). The pH levels of the small intestine were identical in patients and controls, whereas cecal pH was 0.9 pH units higher in resected CD patients. The time spent with pH higher than 5.5, 6.0, 6.5, and 7.0 was significantly shorter in patients than in controls. There was no correlation between the SITT and the length of resected ileum or between the SITT and the time elapsed since the resection. We conclude that ileocecal resection decreases the SITT and the time with pH higher than 5.5-7.0. The study indicates that this reduction of the SITT is mainly due to the resection of the ileocecal valve and is, to a certain extent, independent of the length of resected ileum. An ileocecal resection might therefore affect the delivery of active drug from tablets with pH-dependent delivery.