The present invention relates to the delivery of opioids through an inhalation route. Specifically, it relates to aerosols containing opioids that are used in inhalation therapy. In a method aspect of the present invention, an opioid is delivered to a patient through an inhalation route. The method comprises: a) heating a thin layer of an opioid, on a solid support, to form a vapor; and, b) passing air through the heated vapor to produce aerosol particles having less than 5% opioid degradation products. In a kit aspect of the present invention, a kit for delivering an opioid through an inhalation route is provided which comprises: a) a thin layer of an opioid and b) a device for dispensing said thin layer as a condensation aerosol.