A high-volume peripheral intravenous (IV) catheter and method includes an elongate stylet removably disposed in the lumen of an elongate catheter with the stylet having a beveled distal end forming a piercing tip that protrudes from the outlet port of the catheter. The catheter has a proximal cylindrical shape from the inlet port transitioning at a transition to an inner lumen conical taper terminating at the outlet port, and having a larger internal diameter at the inlet port and a tapering smaller internal diameter between the transition and the outlet port. A plurality of side outlet ports is formed laterally through the catheter in the inner lumen conical taper. A cross-sectional area of the outlet port and the side outlet ports together is equal or greater than a cross-sectional area of the inlet port.