The diagnosis and treatment of severe head and neck infections is a difficult problem for the oral and maxillofacial surgeon. These infections remain an important health problem, with significant risks of morbidity and mortality, if the situations likely to develop a fatal state are not recognized in due time. Due to the variety of antibiotics, the development of new treatment regimens and the safety of surgical techniques as well, the rate of complications of head and neck infections decreases, especially when the medico-surgical intervention is carried out in due time. Phlegmon and necrotizing cervical fasciitis, the most severe forms, are the consequence of acute and diffuse infections, favored by the deficient immunological background, having a mandibular molar tooth as the most frequent etiological factor. The infectious process has a local expansive tendency, through the infiltration and destruction of cervical tissue, following the anatomical cleavage plans and an aggressive course, with a rapid deterioration in the general condition, endangering the life of the patient. Patients with head and neck infections who arrive late at the oral and maxillofacial surgery clinic and whose treatment has been delayed or misbehaved can expect more complications and the recovery period is extended. Early recognition of potentially fatal head and neck infections of dental origin: Emilia Ianes, Serban Rosu, Felicia Streian, Adriana Rosu Timisoara, Romania