Quantitative analysis of gallbladder emptying is important in diagnosis of motility disorder of gallbladder and in studies of biliary physiology. However, the normal range of gallbladder ejection fraction (GBEF) has not been determined yet and the best method for stimulating the gallbladder to contract has not been elucidated adequately. The purpose of this study was to compare the gallbladder emptying effect of the fatty meal ingestion with that of the continuous infusion of cholecystokinin (CCK) and to establish the normal GBSF values of normal subjects. Quantitative hepatobiliary scan with $^{99m}Tc-DISIDA$ after a fatty meal was performed for 22 normal healthy volunteers. Among them, 10 subjects repeated the test with a fatty meal. Again, for 7 subjects quantitative heaptobiliary scan with an infusion of CCK (sincalide) at a rate of 20 ng/kg/hr for 45 minutes was performed repeatedly. The results were as follows. 1) With a fatty meal, the mean GBEF was $89.6{pm}8.2%$ in 22 normal subjects, and there was no difference between subjects. 2) With a continuous infusion of CCK, the mean GBEF was $62.4{pm}16.6%$ in 7 normal subjects, and there was a significant difference between subjects(p<0.05). 3) The reproducibility of GBEF by a fatty meal was significantly higher than by an infusion of CCK (p < 0.05). 4) The mean GBEF by a fatty meal was significantly higher than that by an infusion of CCK (p < 0.05). We concluded that a fatty meal is superior to a continuous infusion of CCK for inducing gall-bladder contraction because that induces more complete emptying and the response is more reproducible and constant.