Table 1.

Baseline characteristics of study and placebo groups

	Study group	Placebo group	P
Demographic characteristics
Number	38	36
Sex ratio (M/F)	15/23	16/20	0.665
Mean age (yr)	64.29 ± 13.40	63.36 ± 15.13	0.781
Etiology			0.972
Choledocholithiasis (cases)	33	31
Others(cases)	5	5
Cholangiectasis (cases)	26	20	0.254
Treatment			0.841
Choledochostomy	26	26
Stent intervention	6	6
Sphincterotomy and drainage	6	4
ERCP operating time (min)	36.89 ± 20.51	40.00 ± 24.73	0.558