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

Meds to Try Instead for Allergies Second-generation Antihistamines Second-generation oral antihistamines are very effective at treating seasonal allergies. —Jessica Swirble, Verywell Health, 7 Apr. 2026

Some over‑the‑counter products that can pose risks include certain antihistamines, commonly found in allergy and cold remedies, nighttime sleep aids, motion sickness medications, and cough syrups, which can induce sleepiness or slow down cognitive function. —Amanda Greenwood, MSNBC Newsweek, 1 Apr. 2026

Otherwise, the bites can be treated with topical itch creams and antihistamines. —Fort Worth Star-Telegram, 30 Mar. 2026

Steroid sprays reduce inflammation, while antihistamines block the body’s allergic response. —Matthew Kayser, USA Today, 25 Mar. 2026

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