Abstract: A novel self actuating anti-reflex device is provided having two anti-reflex valves in fluid connection with each other and cooperatively functioning whereby the first self actuating valve permits passage of fluid and/or gaseous matter therethrough yet senses fluid or gaseous pressure within, for example, an attached receptacle for receiving the matter being passed therein and effectively closes the passageway to the receptacle in response to the fluid and/or gaseous pressure, whereby the second anti-reflex device self actuates permitting fluid and/or gaseous matter to exit therefrom wherein the second anti-reflex valve may optionally be made inoperative. A novel, fully portable drainage collection system incorporating the foregoing self actuating anti-reflex device is also provided and made adaptable for use in connection with the drainage of gastric matter using conventional gastric systems including suction systems in conjunction with the gravity drainage of gastric matter from patients.