Effects of cocaine abuse on the oral mucosa are still poorly defined. Herein, a case of an 18-year-old male patient with a 15-day history of persistent painful ulcers and aphthous lesions of unknown etiology and with no other remarkable manifestations, is presented. All of the laboratory tests performed showed to be within normal ranges. Only subsequently, the patient admitted a cocaine abuse, through smoking and rubbing, over the last 15 days. Finally, after 15 days of interruption of cocaine abuse the oral lesions showed complete regression.