Gingival hyperplasia is a typical adverse reaction of certain drugs (phenytoin, calcium antagonists and cyclosporine). Also oral contraceptives and presumably hormone replacement therapy may rarely lead to gingival hyperplasia. By differential diagnosis a paraneoplastic syndrome has to be taken into account. Drug induced gingival hyperplasia is reversible when the therapy is stopped or modified. If a change of medication is not possible oral hygiene and prophylaxis is critical.