The nationwide shortage of urokinase that began in late 1998 forced the medical community to find suitable alternatives to this agent for the management of various thrombotic processes. A high-use indication for urokinase in our institution is the management of occluded central venous catheters. A comprehensive search of the medical, pharmacy, and nursing literature produced limited but useful information on various alternative agents, including streptokinase, alteplase, hydrochloric acid, ethanol, and sodium hydroxide. This article reviews the available literature on each of these agents.