Odontogenic infections are the most common type of infections of the head and neck among adults. They usually spread continuously from the mandible and/or maxilla into the sublingual, submandibular or masticatory spaces, then directly into the parapharyngeal space. They require comprehensive diagnostic and therapeutic management, as they may potentially lead to life-threatening complications. We present two clinical manifestations of aggressive abscesses in the head and neck region of probable odontogenic origin and discuss different therapeutic approaches. The first patient, a 31-year-old man, was admitted because of a tumor-like lesion within the right maxillary sinus. He complained of purulent nasal discharge of two weeks duration despite antibiotic therapy. In the Caldwell-Luc operation a cyst filled with puss was displayed, the sac of the cyst and the polypoid mass were removed. The second patient, a 28-year-old man, was admitted due to an abscess of the left half of the neck and viscerocranium, with a large edema of this area, neck pain, fever, dyspnea and lockjaw. The patient was qualified for surgery. During intubation, a purulent collection emptied into the oral cavity and throat. In both cases, simultaneously with the surgery, an empirical broad-spectrum antibiotic therapy was administered. Microbiological analysis of the material collected during the operations revealed Prevotella melaninogenica in the first case, and Streptococcus group C in the second. Treatment of aggressive odontogenic infections must take a comprehensive approach, including both surgical intervention and antibiotic therapy covering Gram-positive as well as Gram-negative aerobic and anaerobic pathogens.