Diphenhydramine is an ether that is the benzhydryl ether of 2-(dimethylamino)ethanol. It is a H1-receptor antagonist used as a antipruritic and antitussive drug. It has a role as a H1-receptor antagonist, an antiemetic, a sedative, an anti-allergic agent, a muscarinic antagonist, an antiparkinson drug, an antipruritic drug, a local anaesthetic, an antidyskinesia agent, an antitussive and a oneirogen. It is an ether and a tertiary amino compound.