ABSTRACT: Drug-influenced gingival enlargement is considered to be an important side effect related to the use of some medications and often produces important esthetic changes for patients, as well as clinical symptoms such as pain, bleeding, abnormal tooth movement and occlusion problems. Anticonvulsants, immunosuppressants and antihypertensive drugs have been reported as the main inducers of these periodontal disorders. This case report describes the 4-year clinical follow-up of a young patient with a history of excessive gingival enlargement as a consequence of drug therapy for epilepsy (phenytoin and phenobarbital); the nonsurgical periodontal treatment of the excessive gingival enlargement was associated with the replacement of the patient’s epilepsy medications with valproic acid. We conclude that intensive mechanical control of bacterial biofilms, instruction on oral hygiene guidelines and behaviors and the substitution of alternative anticonvulsant medications are the best way to control the drug-influenced gingival enlargement.