Introduction: Pneumomediastinum is defined as the presence of free air in the mediastinum. The most common manifestations of this disease include pain of the neck, chest pain and dyspnea. We distinguish primary (spontaneous) and secondary pneumomediastinum. Primary (spontaneous) pneumomediastinum is caused by increase of intrathoracic pressure (e.g. coughing, vomiting, and sudden inhalation) with subsequent rupture of alveolar membrane and penetration of air into the fascial layers of mediastinum. It is a state with minimal complications and with good tendency of spontaneous recovery. We find, especially in foreign literature, numerous mentions of the connection between abuse of addictive substances (amphetamines, cocaine, marihuana, heroin) and the occurrence of primary pneumomediastinum (1,9,13-17). This condition has to be distinguished from secondary pneumomediastinum, which is caused by penetration of air into the mediastinum via trauma (external trauma, endoscopy of digestive tract, intubation, foreign bodies) or rupture of aerodigetive tract (sudden abdominal disorder, pulmonary emphysema). Secondary pneumomediastinum is only a symptom of pathology which is potentially fatal and needs causal treatment. Case report: A patient (22 years) under the influence of alcohol was examined in the early morning hours at an ENT emergency after experiencing several hours of neck pain with a feeling of light pressure on the chest. With the diagnosis of acute pharyngitis he was sent to home care. A few hours later, the patient returned to an ENT emergency after the condition had deteriorated and the "swelling of the throat" resumed once again. Clinical examination showed subcutaneous emphysema with crepitation. The patient was promptly admitted for further diagnosis. The performed CT scan confirmed extensive pneumomediastinum. By the detailed analysis of patient's history, laboratory results and clinical examination, we excluded secondary pneumomediastinum. Toxicological analysis of urine confirmed hidden abuse of addictive substance- MDMA (3,4- methylendioxy-N- -methy-amphetamine), so- called Extasy. The condition was summarised as pneumomediastinum caused by ingestion of addictive substance. A control CT scan after conservative treatment showed significant regression of the pneumomediastinum. The patient was sent to home care and to care of general practitioner on the fifth day of hospitalization. Conclusion: Primary pneumomediastinum is a condition, very rarely bringing patients to acute treatment. Due to the character of complaints (neck pain, dyspnea), ENT emergency can be the first place of contact, as is documented by our experience. Primary (spontaneous) pneumomediastinum is a self-limiting condition with minimal complications, in some cases connected with abuse of addictive substances. It is imperative to exclude secondary pneumomediastinum in order to prevent potentially fatal complications. [ABSTRACT FROM AUTHOR]