antihistamine

noun

an·​ti·​his·​ta·​mine ˌan-tē-ˈhi-stə-ˌmēn 

-mən, 

ˌan-tī-

: any of various compounds that counteract histamine in the body and that are used for treating allergic reactions (such as hay fever) and cold symptoms

antihistamine adjective

antihistaminic

ˌan-tē-ˌhi-stə-ˈmi-nik 

ˌan-tī-

adjective or noun

Examples of antihistamine in a Sentence

Recent Examples on the Web

The best response is to remove the stinger quickly with a fingernail, then apply a cold compress and take antihistamines or pain relievers as needed. —Taryn White, Travel + Leisure, 20 Dec. 2025

In addition to the drugs, blood tests revealed that the comedian had taken the antidepressant Prozac and an antihistamine — but neither of those had contributed to his death, according to the Los Angeles Times. —Lynsey Eidell, PEOPLE, 18 Dec. 2025

This is the active ingredient in Benadryl, an antihistamine. —Patty Weasler, Verywell Health, 24 Nov. 2025

Unusually vivid dreams and nightmares are also recognized side effects of other prescription medications and even some over-the-counter drugs such as sedating antihistamines. —Stacey Colino, Time, 3 Nov. 2025

Word History

First Known Use

1946, in the meaning defined above

Kids Definition

antihistamine

noun

an·​ti·​his·​ta·​mine ˌant-i-ˈhis-tə-ˌmēn 

-mən, 

ˌan-ˌtī-

: any of various drugs used for treating allergic reactions and cold symptoms

Medical Definition

antihistamine

1 of 2 adjective

an·​ti·​his·​ta·​mine ˌant-i-ˈhis-tə-ˌmēn, ˌan-ˌtī-, -mən 

: tending to block or counteract the physiological action of histamine

human blood lacks antihistamine activity

antihistamine

2 of 2 noun

: any of various compounds that oppose the actions of histamine and are used especially for treating allergic reactions (as hay fever), cold symptoms, and motion sickness