Deep neck infections were flirty common and a source of considerable morbidity and mortality. Although the advent of antibiotics has reduced the overall number of deep neck infections, they still occur in the general population. There are several new groups of patients at risk for deep neck infections, such as immunocompromised individuals, those with underlying diseases. Prevention of the severe sequale that may be associated with deep neck infections- mediastinitis, airway obstruction, carotid artery hemorrhage, aspiration pneumonia, septicemia - requires a knowledge of various portals of entry for infection, the presenting sign and symptoms, the possible microbiologic features, appropriate laboratory and radiologic workups, therapeutic techniques, and the ongoing medical management. A prompt diagnosis and institution of therapy will shorten the course of required treatment and reduce morbility and mortility. The authors have experienced one case of acute mediastinitis in deep neck infection patient with diabetes mellitus.