Infection is a clinic-pathological entity involving invasion of the body by pathogenic microorganisms and relation of tissues to micro organisms and their toxins. Soft tissue infections of head and neck are commonly encountered in routine practice of oral and maxillofacial surgery. These infections can be odontogenic and non odontogenic origins. But by and large the odontogenic infections are far more common. In most of the clinical situations it is easy to determine whether the patient has an infection. Locally, the classic signs and symptoms of pain, swelling, surface erythema, and lymphadenopathy, and systemically, fever, malaise, toxic appearance, and an elevated white blood cell count is found. But, occasionally a deep-seated infection will not show any external signs except the toxic appearance.