Abstract: This invention discloses a chamber adapted for the administration of medication from a source of aerosolized drug, such as a metered dose inhaler (MDI) or nebulizer, comprising a conduit with an oval cross section, a mounting for the MDI at the rear, an annular one-way valve at the front in fluid communication with the inhalation airway of the patient that permits air to flow out of the chamber during an inhalation by the patient, but prevents exhaled air from entering the chamber, an exhaust valve in the front section that provides an effective seal during inhalation, and a solid state whistle, wherein the whistle is adapted to making a sound if the air pressure within the chamber is below a predefined threshold. The inventive chamber may be used to directly administer inhaled medication to the mouth of a patient, or it may be used with an inhalation mask.