Diphenhydramine is an antihistamine with antihistamine H1 receptors, strong inhibitory effects on the central nervous system, and atropine-like effects, and is used in allergic diseases of the skin and mucous membranes, such as urticaria, chilblain fever, and allergic rhinitis. It can also be used to prevent motion sickness, seasickness, airsickness and other motion sickness. Its adverse effects are some drowsiness, dry mouth and dizziness. There are also sedative, hypnotic and cough suppressant effects. In the process of using it, you must pay attention to its side effects and avoid working at heights, driving, cycling and so on. Maternity is prohibited.