To provide an excellent gingival hypertrophy inhibitor.

This gingival hypertrophy inhibitor contains a compound having angiotensin II antagonism, its prodrug or its salt. The compound having the angiotensin II antagonism preferably comprises a compound expressed by formula (I) [R1 is an anion-formable group or a group which can be changed into the anion-formable group; X is a linkage which joins the phenylene and the phenyl directly or through a spacer comprising two or less atomic chains; A is a benzene ring which may be further substituted; R2 is an anion-formable group or a group which can be changed into the anion-formable group; R3 is a hydrocarbon residue which may be bonded through a hetero atom or may be substituted; and n is 1 or 2] and more preferably comprises Losartan, Eprosartan, Candesartan cilexetil, Candesartan, Valsartan, Telmisartan, Irbesartan, Olmesartan or Tasosartan.