Pericoronitis is an infectious disease often associated with the eruption of a third molar. It can be either acute (serous and suppurative) or chronic. Pain is usually the predominant symptom in acute stages, whereas chronic forms of the disease may display very few symptoms. Both present exudate. The infection is multimicrobial, predominantly caused strictly by betalactamase-producing anaerobeic microorganisms. Treatment measures are symptomatic, antimicrobial and surgical. Antimicrobial treatment is indicated for preoperative prophylaxis when there is a high risk of postoperative infection and, during the acute stages of suppurative pericoronitis when surgery must be postponed. First-line treatment in this case consists of amoxicillin with associated clavulanic acid. Although surgical treatment of pericoronitis presenting at the third molar is indicated as a Grade C recommendation for extraction, it is the most common indication for extraction of a retained third molar, owing to the improved quality of life it can offer the patient.