Abstract: A dispenser and dispenser closure for storing two products separately in and on a necked container for eventual mixing thereof and dispensing them as a mixture. A sealed cup-shaped plug closes the container and has a bottom that is punchable or pierceable. The container contains a first material that is to be mixed with a second material contained in the cup-shaped plug externally of the container interior. A dispensing element which is a tubular punching piston is disposed slidable axially in the cup and is provided with a leading edge at an inner open end for punching or piercing the plug's bottom for introducing the second material into the container upon being depressed. The punching piston fixed therein coaxially therewith a dispensing tube open at both ends. A removable cover closes an outer end of the tube and removed therefrom automatically upon the punching piston being displaced.