Abstract: Catheter patency flow-flush controller comprising push-button valve mechanism with fast flow flush path surrounding the valve member, normally closed by a valve element and valve seat interposed between the inlet and outlet of the internal passageway of the controller by a coil spring located external of the internal passageway, the coil spring also compressively retaining a resilient seal at all times about the entry way through which the valve plunger enters the controller internal passageway. Preferably, the valve member push-button actuator includes a top cap member with dependent skirt which serves also as an alignment guide during valve movement by sliding engagement with an upwardly open skirt associated with the controller housing. Other features of the invention are also disclosed and claimed.