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

Most people find relief with over-the-counter antihistamines like Claritin, Zyrtec, or Allegra, or nasal sprays such as Flonase. —Matt Leclercq, Fort Worth Star-Telegram, 26 Jan. 2026

Some medicines, such as Benadryl Allergy and Claritin-D, act as a decongestant and antihistamine. —Bestreviews, Chicago Tribune, 23 Jan. 2026

The autopsy also found the presence of prescription antidepressant and antihistamine medications, adding that Lunas Campos had a history of bipolar disorder and anxiety. —CBS News, 22 Jan. 2026

Nonsedating antihistamines like those found in Zyrtec or Allegra can help control itching and sneezing during the day. —Miriam Fauzia, Dallas Morning News, 20 Jan. 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