This report describes a case of gingivitis in a 15-year old boy who had recently (1-2 days previously) stored an ecstasy tablet between his upper lip and gums ("upper anterior labial vestibule"). Prior to referral, the boy experienced a one-day history of general malaise, fever and painful upper anterior lip swelling. He had a record of good dental hygiene. The ulceration was treated by incision, draining and antibiotics. Swelling was reduced 2 days later, and the teeth were in good health, with the ulcer healing one week later. The area adjacent to gingivitis was not affected, perhaps due to at least one of the following; difference in tissue type, exposure to salivary flow, or means by which the ecstasy tablet was held in place. Though this is the first case in the literature of a periodontal ulcer arising from local MDMA application, the authors indicate that similar conditions have arisen after local cocaine application, and suggest that the effects are due to local vasoconstriction at the site of application. The author also lists acute MDMA effects with possible dental consequences (namely bruxism, and jaw clenching).