A rare benign overgrowth of fibrous tissue of hereditary or idiopathic origin primarily affecting children and young adults. It is characterized by painless firm hyperplastic tissue enlargement of the gingivae which covers the teeth; there may also be associated gingival inflammation and bleeding where the oral hygiene is poor; one or more quadrants of the mouth may be affected. It is treated by wide excision (gingivectomy), although it has a locally aggressive behaviour possibly leading to recurrence. The condition of fibrous gingival hyperplasia may also be drug-induced, e.g. by phenytoin or nifedipine, in which the hyperplasia occurs three or more years after the onset of drug use; treatment is by plaque control and may also include a change in drug therapy. Symmetrical fibromatosis of the tuberosity can occur in adults and is characterized by large, smooth, fleshy, hyperplasia of the tissues overlying the maxillary tuberosities; treatment is usually unnecessary unless there is interference with a denture fitting surface.