ABSTRACT: Anticonvulsants are drugs that can modify the gingival tissues response to inflammatory processes in the presence of dental plaque, inducing gingival overgrowth. Preexisting gingival inflammation induced by dental plaque seems to be a favorable condition to the development and/or expression of gingival overgrowth. This study describes a case in which the use of phenytoin and phenobarbital anticonvulsant associated with the presence of dental plaque provided a large and severe extent of gingival alteration. We concluded that it was possible to achieve a good result in the patient with an intensive mechanical control of dental plaque, oral hygiene orientations and substitution of the drug for other alternative medication.