Dihydroergotamine (dhe) (or phentolamine), an alpha-adrenergic blocking agent, induced important changes on the CCK-stimulated gallbladder emptying of 70 volunteer subjects. Two cholecystograms were performed with 10-day intervals in each subject. The first cholecystogram showed gallbladder emptying provoked by a test meal (35 subjects or by 0.5 U. CCK Kg. injected intravenously (35 subjects). During the second cholecystogram 1 mg. of DHE was injected intramuscularly 45 minutes befor the cholecystokinetic stimulus. The drug counteracted the gallbladder emptying induced by both endogenous and exogenous CCK. The effect was more pronounced when DHE was administered prior to the test meal stimulus than before CCK administration. This difference could be explained by a delayed gastric emptying induced by the alpha-adrenergic blockade. Our results suggest that the lack of gallbladder emptying could be due to the relaxation of this organ, in addition to a duodenal spasticity induced by DHE (or phentolamine).