Odontogenic acute mediastinitis is an polymicrobial infections caused in most cases by gram negative and anaerobic germs. The odontogenic origin of the cases in this study was based on anamnestic inquiry of the patients, which reveales a dental treatment 7-15 days before the diagnosis of acute mediastinitis was established. Clinical features are often nonspecific at the debut of this affection; septic shock could appear suddenly associated with multiple systems and organs failure. This is the explication why, some of these patients presented septic shock when are diagnosed. In this situations, when acute mediastinitis is suspected, based on clinical and imaging findings, it must be confirmed by surgical exploration and perioperative bacteriological evaluations. Positive diagnosis is based on clinical features associated with labs and imaging studies. Surgery plays an important role in therapy of acute mediastinitis: debridement and drainage of mediastinum with subsequently lavage of it, using antiseptic solutions. Broad spectrum antibiotherapy should be administrated immediately, before antibiogram is ready.