Abstract: A bi-directional flow catheter for insertion into the body of a patient for the simultaneous introduction into and withdrawal therefrom of fluid. The catheter includes a primary tube having open distal and proximal ends, and a pair of branching tubes, each of which branch from a different side of the primary tube. The primary tube also has an opening in one side thereof to allow introduction of fluid. An elongate trocar/valve member is disposed in the primary tube and is movable longitudinally therein between an insert position and a flow position. One end of the trocar/valve member tapers to a cutting edge which protrudes from the opening in the distal end of the primary tube when the member is in the insert position. The trocar/valve member is formed to prevent communication between the side opening and the opening in the distal end of the primary tube, and to cover the passageways between the primary tube and respective ones of the branching tubes when the member is in the insert position.