Descending necrotizing mediastinitis secondary to dental infection occurs infrequently. The diagnosis of this condition is difficult and often a surgical approach is delayed due to initial clinical improvement after antimicrobial therapy. An incorrect evaluation of this apparent improvement may result in fatal mediastinitis and septic shock. We report 3 cases of mediastinitis of odontogenic origin. In one patient, a nonproductive cough was the first sign of thoracic involvement. A total of 25 similar cases of mediastinitis from odontogenic infection have been collected from the literature in the last 15 years. Some features have to be emphasized, such as the polymicrobial flora, the higher prevalence in males, and the high mortality rate of approximately 44%.