A histamine H1 antagonist used as an antiemetic, antitussive, for dermatoses and pruritus, for hypersensitivity reactions, as a hypnotic, an antiparkinson, and as an ingredient in common cold preparations. It has some undesired antimuscarinic and sedative effects.

Synonyms: Allerdryl, Benhydramin, 2-Diphenylmethoxy-N,N-dimethylethylamine, Benadryl, 4OD433S209, Diphenhydramine, Diphenhydramine Citrate, 8GTS82S83M, TC2D6JAD40, 0, Dormin, Citrate, Diphenhydramine, Diphenhydramine Hydrochloride, Dimedrol, Ethanamine, 2-(diphenylmethoxy)-N,N-dimethyl-, Benylin, Hydrochloride, Diphenhydramine, Benzhydramine, Diphenhydramine Citrate (1:1), Diphenylhydramin, Diphenylhydramine