Abstract: A catheter device, comprising a venipuncture needle or stylet whose shank extends through the bore of a catheter or cannula and has a sharpened tip projecting slightly therebeyond in an extended position of the needle to provide an outside-the-needle catheter unit for venipuncture and for insertion of the catheter in a vein in largely conventional manner, and a housing adapted to define an elongate liquid flow chamber. Such housing is connected, liquid-tight, at one end to the catheter and is adapted to protectively house the sharpened tip of the needle following venipuncture. The housing itself is liquid-tight, except for an opening at its other end through which extends tubing for the supply of a venoclysis liquid. The other end of the needle may be provided with a hub formed as a stopper for fitting tightly in a seat formed in the housing immediately in advance of the opening, or may be provided with a hub that is attached to the supply tubing at the opening.