Can Dogs Have Benadryl? How Much Benadryl Can I Give My Dog?

If your dog’s constant scratching or sneezing has you wondering, “Can I give my dog Benadryl?” — you’re not alone. Pet parents everywhere are looking for safe ways to bring their pups relief from allergies and itching. Before you reach for the pink tablets, here’s what every responsible dog owner should know about using Benadryl, why your dog might be itching in the first place, and how to get to the root of the problem.

Understanding Benadryl and How It Works

Diphenhydramine hydrochloride, most commonly known as Benadryl, is an antihistamine often used in humans to relieve allergy symptoms like runny noses, watery eyes, and itching¹. In dogs, it works much the same way — by blocking the histamines that cause allergic reactions.

But it’s not a cure-all. While Benadryl may be appropriate for occasional use to alleviate mild symptoms, it doesn’t resolve the underlying cause of your dog’s discomfort.

If your dog is displaying any acute allergic reactions, such as swelling or difficulty breathing, they should be immediately taken to the vet, as this is a life-threatening situation.

Jocelyn LambieJunior Nutritionist

How Much Benadryl Can I Give My Dog?

Just like any medication, a proper dose should always come from your veterinarian. There are many references which offer suggestions, including the Merck Veterinary Manual.

However, never medicate your dog without talking to your veterinarian first. Benadryl will be dosed by a veterinarian based on their size and weight, so it is best to confirm the appropriate dosage amount with them, prior to self-medicating your dog. Dogs with certain health conditions — like heart disease, glaucoma, high blood pressure, or pregnancy — may react poorly to Benadryl². Some working dogs (such as German Shepherds and Border Collies) have genetic sensitivities to specific medications and should be treated with extra caution².

Does Benadryl Make Dogs Sleepy?

Yes — drowsiness is one of the most common side effects. Too much can cause extreme lethargy or even agitation in some dogs.

If your dog seems unusually tired or uncoordinated after taking Benadryl, contact your vet right away.

Why Is My Dog So Itchy in the First Place?

Allergies in dogs can stem from many sources, including their environment. Before asking, “What can I give my dog for allergies and itching?”, it’s important to first identify the source of your dog’s allergies.

In fact, food intolerances are one of the most overlooked causes of chronic itching. Symptoms can include red skin, paw licking, ear infections, or recurring digestive upset. In these cases, Benadryl might provide short-term relief but won’t solve the real issue — what your dog’s eating.

A 2015 study in BMC Veterinary Research found that up to 24% of dogs with chronic skin issues were reacting to food ingredients⁵.

Jocelyn LambieJunior Nutritionist

Recommended Solution

Limited Ingredient Dog Food Made by Pet Nutrition Experts

These grain-free, gluten-free, and chicken-free recipes limit contact with common food allergens — providing all the nutrition your dog needs using as few key ingredients as possible.

View Sensitivities dog food

How to Help a Dog with Allergies (Beyond Medication)

If you’re reaching for Benadryl regularly, it may be time to dig deeper into why your dog is itchy.

Getting your dog’s diet right can be life-changing – when their allergies calm down, their coat softens, their happy energy returns, and that endless scratching finally stops!

Key Takeaway: Relief Starts with Understanding

Benadryl can be helpful for short-term relief in some cases, but it’s not a long-term fix — especially if your dog’s discomfort is food-related. The best way to help your dog feel better is to uncover the root cause of their symptoms. With your vet’s help and the possibly the right nutrition, your dog can get back to feeling like their happy, tail-wagging self.