diphenhydramine

American  

[dahy-fen-hahy-druh-meen] / ˌdaɪ fɛnˈhaɪ drəˌmin /

noun

Pharmacology.

1. a white, crystalline, antihistaminic compound, C 17 H 21 NO, used orally, topically, and parenterally, especially for allergies.

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Etymology

Origin of diphenhydramine

First recorded in 1945–50; diphen(yl) + hydr- ² + amine

Example Sentences

Anticholinergics also include diphenhydramine, the active ingredient in over-the-counter products like Benadryl.

From The Wall Street Journal • Jan. 8, 2026

And while sedating antihistamines like diphenhydramine might help you sleep at night, they don't treat the cough itself.

From BBC • Dec. 3, 2025

About 40% of incidents involved common over-the-counter medications, such as acetaminophen, ibuprofen and diphenhydramine.

From Seattle Times • Apr. 21, 2023

The over-the-counter antihistamines I used to take, which contain diphenhydramine, “were never really systematically studied for their effects on sleep,” Dr. Krystal said.

From New York Times • Apr. 7, 2022

Taking antihistamines such as diphenhydramine at night can slightly reduce itchiness and it has the benefit of helping you sleep better.

From Washington Post • Sep. 10, 2021