SHEET /m/diphenhydramine · PubChem CID 3100 · CAS 58-73-1 · REV 2026.07

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Diphenhydramine

from source

C17H21NO · 255.35 g/mol

benzhydramine · dimehydrinate · Dimedrolum · Allergina

Also sold as Benadryl, ZzzQuil, Sominex from source

What is Diphenhydramine?

The antihistamine in Benadryl, used for allergy symptoms and, because it causes drowsiness, in nighttime sleep aids. from source

CategoryOTC medicine

Chemical familyAromatics Ethers

LeaderboardsBiggest Deadliest

Fig. 1 · 2D structure RDKit

SMILESCN(C)CCOC(C1=CC=CC=C1)C2=CC=CC=C2

Where you'll find it

First aid kitwhat else is in it →

Curated by MoleculeFinder from source

Relative acute toxicity from source

Animal study data · LD50

Reported LD50: 500 mg/kg · low toxicity
Species: rat
Route: oral

An LD50 describes acute toxicity under experimental conditions and is not a safe or dangerous dose for a person.

Toxicity & hazards

Toxicity · LD50

500 mg/kg · low toxicity · LD50 rat oral from source

WarningIrritantH302, H315, H319from source

Keep roaming

Where Diphenhydramine leads

Relatedcomputed

Dimenhydrinate50% similarBoth carry an ether group.Doxylamine37% similarBoth carry an ether group.Tamoxifen36% similarBoth carry an ether group.

Compare with

Diphenhydramine vs Cetirizine Diphenhydramine vs Loratadine Diphenhydramine vs Hydroxyzine

Sources & methodology

PubChem CID: 3100
Wikidata: Q413486
Structure: PubChem → RDKit
LD50: PubChem
Similar molecules: MoleculeFinder fingerprint similarity
Everyday relationships: MoleculeFinder editorial curation
Data refreshed: October 19, 2026

How MoleculeFinder sources and labels its data