PURPOSE: The authors evaluated a technique for the prevention of significant hemobilia during placement of transhepatic biliary drainage catheters (TBDCs). PATIENTS AND METHODS: Twenty patients with strictures were randomized to two groups. In the control group, the biliary tree was accessed with an Accustick system and a TBDC was placed routinely. In the experimental group, following initial access, a rotating hemostatic valve was attached and the outer sheath was pulled back over the wire while contrast material was injected. If a major vascular structure was encountered, the tract was not used for TBDC placement. However, the outer sheath was re-advanced and used to opacify the ducts. This facilitated separate access. Once access was achieved without traversing a major vascular structure, a TBDC was placed, and the Accustick system was removed. If a portal vein or hepatic vein branch was traversed, no additional maneuvers were performed. However, if a branch of the hepatic artery had been traversed, the tract and biliary-arterial fistula were embolized with gelatin sponge pledgets. Both groups were evaluated for hemobilia for 6 weeks. RESULTS: In the control group, there were three cases of significant hemobilia; two were mild, one was severe. In the experimental group, the tract communicated with a major vascular structure in three patients. In these patients, a second access was used for TBDC placement. None of the patients in the experimental group experienced significant hemobilia. CONCLUSION: Visualization prevents the usage of tracts that communicate with large vascular structures. Initial results indicate that this reduces the frequency of significant hemobilia when TBDCs are placed.