Ingredient

Diphenhydramine Hydrochloride

Diphenhydramine hydrochloride is an antihistamine used to relieve allergy symptoms and induce sleep.

See medicines used for Mental & Nervous System
All medicines
91
Single ingredient
12
Combination
79
OTC medication
91

MFDS ingredient code M222973

What does it do?

Diphenhydramine hydrochloride belongs to the antihistamine class and is primarily used for alleviating allergy symptoms, aiding sleep, and relieving mild pain. It also helps reduce itching or inflammation.

This ingredient works by blocking the action of a substance called histamine in the body, thus reducing allergic reactions. It also acts on the central nervous system to produce a sedative effect, making it easier to sleep.

Commonly used for

Approved uses differ by product. Check each product's information for its actual use.

Good to know

Diphenhydramine hydrochloride has a stronger sedative effect compared to other antihistamines and is also used as a sleep aid. Consequently, drowsiness is common, distinguishing it as both an allergy treatment and a hypnotic sedative.

Medicines containing this ingredient

Even with the same ingredient, strength, dosage form and how it is taken can differ.

Category
Dosage form
Strength
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91 total

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Even with the same ingredient, dosage and approved uses can differ by strength, dosage form and combined ingredients. Check each product's information before taking it.

Combined ingredients

Ingredients used together with this ingredient in combination products.

Questions about this ingredient

  • QIs it okay to take a sleep aid after taking a runny nose medicine before bed?

    Both cold medications and sleep aids may contain antihistamine ingredients like diphenhydramine, which may overlap in their class of medications. As this may increase drowsiness, please check the ingredient lists of both products and consult with a pharmacist before taking them together. Avoid consuming alcohol while taking them.

    Answers 1 · 2026.09.14

  • QIs this the ingredient included in sleep-inducing medications?

    Diphenhydramine hydrochloride is an antihistamine that acts on the central nervous system to produce a sedative effect, and is therefore also used as a sleep aid. It is used to relieve allergy symptoms as well as itching, and drowsiness is a common side effect.

    Answers 1 · 2026.09.14

For anything that needs medical judgment, consult a doctor or pharmacist.

SourceKorea Ministry of Food and Drug Safety (Drug Safety Korea)

This drug information is based on data provided by the Korea Ministry of Food and Drug Safety.
Consult a doctor or pharmacist for accurate dosage, administration, and usage instructions.