A case of extensive subcutaneous emphysema is reported. The patient had a mandibular third molar extracted but did not experience any cervical edema until the morning after surgery. The emphysema did not appear to be caused by the surgical procedure, as emphysema caused by use of instruments becomes immediately apparent and no patient-related causes could be documented. However, a dressing of a tetracycline-steroid ointment in a petrolatum base and a hemostatic agent was placed in the tooth socket during surgery and the dressing may have allowed air into the deeper tissues. The patient was managed by hospitalization, antibiotic therapy, and rest. The tissue emphysema resolved gradually during a 5-day period.