The ability of hepatobiliary scanning (99mTc HID A) to distinguish gallstone (GS) from non-gallstone (NGS) pancreatitis was investigated in 29 patients. 4 patients had repeat scans during a recurrent attack (33 scans in 29 patients). 15 patients (17 scans) had GS – in 13 scans the gallbladder was not visualized (sensitivity = 76.5%) compared to 2 of the 16 scans in patients with NGS (specificity = 87.5%). The duodenum was not visualized in 2 (11.8%) and 4 (25%) scans in the GS and NGS groups, respectively. Isotope appeared in the duodenum at 25.7 ± 9.2 min (mean ± SD) in the GS group and 33.3 ± 10.5 in the NSG group (p < 0.02). Hepatobiliary scanning provides a dynamic study of bile excretion in acute pancreatitis, but cannot be used alone to confidently diagnose the presence of gallst