A no-spill fluid security system for couplings for use with fluids producing environmental impact wherein the coupling permits unidirectional flow for consumer use and bidirectional flow to permit the refilling of containers with specially designed mating coupling parts. The primary coupling part includes a valve located adjacent the primary part end to prevent spillage and a normally operative check valve prevents fluid flow into the primary coupling part while a secondary coupling part of special construction opens the normally closed check valve permitting unidirectional flow through the primary part. Pressure relief means are incorporated into the primary part to permit trapped fluids within an uncoupled primary part to be bled into the associated receptacle upon a predetermined pressure existing to prevent spillage.