Catheter apparatus for performing diagnostic and therapeutic modalities in the biliary tree includes a catheter with multiple lumens. A first lumen is adapted to receive a guidewire and can serve as a transport lumen for contrast agent. A second lumen carries a cutting wire for performing a sphincterotomy. A third lumen can be used as an inflation lumen for a distally located balloon. Expansion of the balloon occludes a portion of the biliary tree and allows the catheter to sweep any gallstones through the sphincter of Oddi into the duodenum.