In this controlled clinical study, the bioavailability and pharmacodynamics of inhaled heroin are evaluated and compared between 'chasing the dragon' and inhalation from a heating device, and at three dose levels, 25, 50 and 100 mg heroin, in two separate study phases. In study phase 1, no differences between the inhalation methods were detected on any of the physiological or behavioral measures, nor in bioavailability. Subjectively, the participants had a strong preference for the method of chasing, which was therefore used in study phase 2. In phase 2, heroin produced a dose-related increase in subjective drug-liking, body temperature and heart rate, and a clear, dose-related decline in reaction time. Linearly dose-related differences were found in the amount of total morphine in urine, amounting to an average of 45% of the parent heroin base received. Based on these findings, it is concluded that chasing is quite an effective route of heroin administration, producing rapid, dose-related subjective and objective effects and a sufficiently high and reproducible bioavailability.