The authors assessed the influence of cholecystokinin (CCK), administered before cholescintigraphy, on the biliary-to-bowel transit time (BBTT) of technetium-99m disofenin. Fourteen healthy volunteers underwent two separate cholescintigraphic studies with and without CCK treatment. BBTT was less than 1 hour in all 14 studies of subjects not treated with CCK. In 14 subjects treated with CCK, there was no tracer activity in the bowel up to 2 hours in seven (50%) (P = .006). Eighty-three cholescintigrams obtained in patients with suspected acute cholecystitis were also retrospectively analyzed. In 53 of 83 patients in whom the gallbladder was visualized within 1 hour, significantly delayed BBTT was found in 14 of 29 (48%) who received CCK, compared with the BBTT in one of 24 patients (4%) who did not receive CCK (P less than .001). In the 30 patients in whom the gallbladder was never visualized (n = 28) or was visualized after 1 hour (n = 2), BBTT was less than 30 minutes, regardless of whether patients were treated with CCK. Results show that CCK treatment causes significantly delayed BBTT in many cases, and this finding should not be interpreted as abnormal.