A normally closed valve is characterized by an integral valve body forming a fluid passage between an inlet thereto and an outlet therefrom, and a flow barrier within the passage integrally joined with the body to hermetically seal the passage. The barrier is movable or rupturable by a fluid coupler, inserted into the outlet end of the passage, to open the passage between the inlet thereto and the coupler.Preferably, the valve is economically formed of a plastic material, such as polyethylene, and connects at its outlet with a fluid coupler having a normally closed, movable seal at its inlet. In the use of the valve, upon movement of the inlet end of the coupler into the outlet end of the passage, the valve passage forms a fluid seal therewith prior to engagement of the barrier thereby. Continued movement of the coupler into the valve then moves the flow barrier to open the passage, and engages the coupler seal with a plunger to move the seal from a seat at the inlet to the coupler to establish the fluid passage between the inlet to the valve passage and the inlet to the coupler. In consequence of forming a seal between the valve and coupler prior to opening of either the flow barrier or the coupler seal, a connection may be established between the coupler and the valve in a drip-free manner, and the fluid to be valved is at all times maintained out of contact with the atmosphere and in a sanitary condition.