Spontaneous pneumomediastinum, defined as the presence of free air in the mediastinal structures, is a rare disease that usually take a good course with conservative therapy. However, clinicians are usually unfamiliar with the disease because of its infrequency. We report herein a case of spontaneous pneumomediastinum following an episode of violent cough. The patient was treated conservatively after hospitalization and got well without any medical problems. In addition we reviewed characteristics of spontaneous pneumomediastinum reported so far in the Japanese literature. The result of our review suggests that the typical patient with spontaneous pneumomediastinum is a young man with a slender build. In most patients, spontaneous pneumomediastinum occurs in conjunction with condition causing high airway pressure. None of the patients described in the literature developed serious complications such as cardiac insufficiency or airway compromise, and none of the cases without concomitant pneumothorax required any medical care. In conclusion, familiarity with this rare disease is crucial to provide appropriate treatment