Acute pancreatitis is a severe complication of gallstones with considerable mo rtality. We sought to explore the potential risk factors for biliary pancreatiti s. We compared postprandial gallbladder motility (via ultrasonography) and, afte r subsequent cholecystectomy, numbers, sizes, and types of gallstones; gallbladd er bile composition; and cholesterol crystallization in 21 gallstone patients wi th previous pancreatitis and 30 patients with uncomplicated symptomatic gallston es. Gallbladder motility was stronger in pancreatitis patients than in patients with uncomplicated symptomatic gallstones (minimum postprandial gallbladder volu mes: 5.8 ±1.0 vs. 8.1 ±0.7 mL;P = .005). Pancreatitis patients had more often sludge (41%vs. 13%; P =.03) and smaller and more gallstones than patients with symptomatic gallstones (smallest stone diameters:2 ±1 vs. 8 ±2 mm; P = .001). Also, crystallization occurred much faster in the bile of pancreatitis patients (1.0±0.0 vs. 2.5 ±0.4 days; P < .001), possibly because of higher mucin conce ntrations (3.3 ±1.9 vs. 0.8 ±0.2 mg/mL; P = .04). No significant differences w ere found in types of gallstones, relative biliary lipid contents, cholesterol s aturation indexes, bile salt species composition, phospholipid classes, total pr otein or immunoglobulin (G, M, and A), haptoglobin, and α-1 acid glycoprotein concentrations.In conclusion, patients with small gallbladder stones and/or pres erved gallbladder motility are at increased risk of pancreatitis.The potential b enefit of prophylactic cholecystectomy in this patient category has yet to be ex plored. We sought to explore the potential risk factors for biliary pancreatiti s. We compared postprandial gallbladder motility (via ultrasonography) and, afte r subsequent cholecystectomy, numbers, sizes, and types of gallstones ; gallbladder erbile composition; and cholesterol crystallization in 21 gallstone patients wi th previous pancreatitis and 30 patients with uncomplicated symptomatic gallston es. Gallbladder motility was stronger in pancreatitis patients than in patients with uncomplicated symptomatic gallstones (minimum postprandial gallbladder volu mes: 5.8 ± 1.0 vs. 8.1 ± 0.7 mL; P = .005). Pancreatitis patients had more often sludge (41% vs. 13%; P = .03) and smaller and more gallstones than patients with symptomatic gallstones (smallest stone diameters: 2 ± 1 vs. 8 ± 2 mm; P = .001). Also, the number of changes in the bile of pancreatitis patients (1.0 ± 0.0 vs. 2.5 ± 0.4 days; P <.0 01), probably because of higher mucin conce ntrations (3.3 ± 1.9 vs. 0.8 ± 0.2 mg / mL; P = .04). No significant differences found in types of gallstones, relative biliary lipid contents, cholesterol s aturation indexes, bile salt species composition, phospholipid classes, total protein or immunoglobulin (G, M, and A), haptoglobin, and alpha-1 acid glycoprotein concentrations. conclusion, patients with small gallbladder stones and / or presserved gallbladder motility are increased risk of pancreatitis. potential b enefit of prophylactic cholecystectomy in this patient category has yet to be ex plored.