One of the clinically significant rate-limiting components in even the fastest of intravenous (IV) fluid systems is the tubing connecting the IV catheter to the IV solution container. We evaluated the effect large-bore tubing has on reducing this limitation on fluid flow, measuring gravity and pressurized flow in standard and large-bore tubing alone and when each was connected to an 8 French and 12-,14- and two types of 16-gauge catheters. When combined with an 8 French catheter, large-bore tubing produces a 126% increase in flow under gravity and a 90% increase under pressure. The improvement with the large tubing was less significant as the catheter size decreased. Studies in normovolemic adult volunteers achieved similar results. Large-bore blood tubing and large-bore catheters should be used in all situations where the need for rapid fluid replacement is contemplated.