AIM:To investigate the usefulness of magnetic resonance cholangiopancreatography (MRCP) and the need for endoscopic retrograde cholangiopancreatography (ERCP) in cases of suspected spontaneous passage of stones into the common bile duct.METHODS:Thirty-six patients with gallbladder stones were clinically suspected of spontaneous passage of stones into the common bile duct because they presented with clinical symptoms such as abdominal pain and fever,and showed signs of inflammatory reaction and marked rise of hepatobiliary enzymes.These symptoms resolved and they showed normalized values of blood biochemical parameters after conservative treatment without evidence of stones in the common bile duct on MRCP.All these patients were subjected to ERCP within 3 d of MRCP to check for the presence of stones.RESULTS:No stones were detected by ERCP in any patient,confi rming the results of MRCP.CONCLUSION:When clinical symptoms improve,blood biochemical parameters have normalized,and MRCP shows there are no stones in the common bile duct,it can be considered the stone has spontaneously passed and thus ERCP is not necessary. To investigate the usefulness of magnetic resonance cholangiopancreatography (MRCP) and the need for endoscopic retrograde cholangiopancreatography (ERCP) in cases of suspected spontaneous passage of stones into the common bile duct. METHODS: Thirty-six patients with gallbladder stones were clinically suspected of spontaneous passage of stones into the common bile duct because they presented with clinical symptoms such as abdominal pain and fever, and showed signs of inflammatory reaction and marked rise of hepatobiliary enzymes. thesese symptoms resolved and they showed normalized values ​​of blood biochemical parameters after conservative treatment without evidence of stones in the common bile duct on MRCP. All of these patients were subjected to ERCP within 3 d of MRCP to check for the presence of stones .RESULTS: No stones were detected by ERCP in any patient, confi rming the results of MRCP .CONCLUSION: When clinical symptoms improve, blood biochemical parameters have normalized, and MRCP shows there are no stones in the common bile duct, it can be considered the stone has spontaneously passed and thus ERCP is not necessary.