[Mediastinitis caused by anaerobic bacteria. 4 cases].

In 4 cases of mediastinitis caused by anaerobes and consecutive to dental abscess (2 cases), perforation of the oesophagus and tonsillar abscess, the diagnosis was based on widening of the mediastinum associated, in 2 cases, with pneumomediastinum. II all 4 cases, Bacteroides fragilis was present among other germs. Treatment consisted of surgical drainage by thoracotomy (2 cases), or cervicotomy and antibiotic therapy. Two of the patients, who were old and had underlying diseases, died.