An adaptor for use with a container equipped with a dispensing valve that comprises a valve stem movable between an inner closed or priming position and an outer dispensing position, for dispensing doses of pressurized aerosol formulation as well as dispensers comprising such an adaptor and container; said adaptor being adapted to receive the container and comprising an actuation mechanism, said actuation mechanism being arranged such that the user will operate the mechanism by applying a depressive or squeezing force and the dose will be dispensed upon said depressive or squeezing force and said actuation mechanism being arranged such that upon release of the mechanism by the user, the valve stem of the dispensing valve will be moved automatically into its inner closed or priming position.