Abstract: A self-sealing container closure includes a rotatable cap mounted over the mouth of an oval squeezable container. The cap has an outlet opening defined by a valve seat. The outlet opening is sealed by a valve element forced against the valve seat by a valve spring and a pair of actuating arms. An upper end of each actuating arm is non-rotatably coupled to the cap while the lower end is connected to the valve spring. When the cap is rotated to align the actuating arms with the minimum width of the container, squeezing the sides of the container presses on the actuating arms to further deflect the valve spring. This forces the valve element away from the valve seat to open the container. Rotating the cap, to align the arms with the maximum width of the container, places the container in a non-operational mode. Also disclosed is a piston and cylinder arrangement coupled to the actuating arms for dispensing a measured amount of liquid from the container.