A self-powered vapor pressure delivery device for the controlled and continuous dispensing of an active agent employing in a preferred embodiment outer and inner chambers in functional relationships. The inner chamber is a sealed bag comprised of a flexible and substantially vapor and fluid impermeable material. The bag is freely positioned within an outer casing. The bag is filled with a volatile propellant and is expandably responsive to the vapor pressure of the propellant at the temperature of use, such as to cause the bag to distend so as to reduce the volume of the outer chamber. The active agent in the outer chamber is thereby caused to flow through a flow resistive means which is provided in the outer chamber.