Abstract: A method and apparatus for dispensing inhalable material includes the steps of indicating to a patient that a breath should be taken, detecting the start of inhalation, causing inhalable material to be supplied to the air passages of the patient during a preselected part of the period of inhalation, then after a predetermined inhalation period substantially preventing further inhalation, indicating to the patient that exhalation should begin, detecting the start of exhalation, and after a predetermined exhalation period again indicating that a breath should be taken. The dispenser includes a supply of inhalable material, a mouthpiece, and a control device for selectively controlling the flow between the supply and the mouthpiece, as well as between the supply and the atmosphere. The device also includes a signalling means for indicating to the user when to inhale and subsequently when to exhale.