Three patients are described who developed either pneumomediastinum or "clicking pneumothorax" after abusing illicit drugs. In recent years, patients presenting with pneumomediastinum after abusing cocaine have been frequently reported; these patients are most commonly young males with pleuritic chest pain. Seventy-three percent have detectable subcutaneous emphysema and fifty percent have a Hamman's sign. The pathophysiology, presenting features, and treatment of patients with barotrauma related to inhalational drug abuse are reviewed.