An odontogenic infection is an infection associated with teeth and is most commonly caused by infected root canal while the less common cause can be infected periodontal or pericoronar tooth area. The normal microbal flora of the oral cavity consists of different types of bacteria which can become causative agent of infection if between their pathogenicity and the host defense occur disturbances. The microbial flora of odontogenic infection changes over time in favor of anaerobes. After extension of microorganisms to periapical tissue, the body responses by inflammation that can have acute, subacute and chronical course. The inflammatory process from periapical region usually expands through closer and thinner bone wall, can perforate the periosteum and reach the soft tissue. The localization of the inflammatory process in the soft tissue and the later pathways of the spread depend on the anatomic position of the muscles and head and neck fascias so the abscesses can be formed intraorally or extraorally. Symptoms that are common to most abscesses, include swelling of the tissue, pain, redness of the surrounding mucosa, while in some harder cases, when the infection spreads, complications accompanied by general symptoms may occur. Treatment of odontogenic infection may involve elimination of the affected tooth by extraction or endodontic treatment, drainage of inflammation process by incision, extraction, cortical trepanation or trepanation of tooth, the use of antibiotics, when they are indicated, and some additional measures such as hidratation of organism or use of analgetics if needed. Amoxicillin with clavulanic acid is the most effective antibiotic. If there is no improvement while using amoxicillin with clavulanic acid after local dental treatment for the next two days, metronidazole, that is effective with Gramm (-) anaerobic bacteria, should be ordered.