Pneumomediastinum (Hamann's syndrome) is a very rare condition with various aetiologies. Case reports are found in nearly all medical specialties. Adequate therapy is individualized and strongly related to the organ of origin. In pulmonary diseases such as asthma, treatment of the underlying disease is usually sufficient. Secondary pneumomediastinum following Boerhaave's syndrome or iatrogenic tracheal ruptures, however, requires surgical intervention. Wide chest tubes placed in-to the mediastinum are the best option. The question regarding a correlation between pneumomediastinum and mediastinitis cannot be answered by a review of the literature. Because of the rarity of the disease, evidence-based data about the best therapy are lacking.