Abstract: A kit for starting an I.V. is disclosed, as is a coupling for preventing blood and fluids from spilling out of the kit's catheter. The kit is comprised of a catheter portion, a coupling portion and a flesh piercing portion. The cannula portion includes a cannula having a hub. The coupling portion is comprised of first and second tubular portions, and a septum bound integrally therebetween. The flesh piercing portion is comprised of a needle and a handle. The method disclosed includes the steps of lodging the first tubular portion of a resilient coupling into the hub of a catheter; driving a guide needle axially through the coupling and catheter; driving the coupling and catheter into a vein; and withdrawing the guide needle from the catheter and coupling. Although blood flows into the catheter, it is prevented from flowing beyond the self-sealing septum.