Dogs and Benadryl: Is it safe, and how much can you give?

Written by Marisa Wilson
Published: July 29, 2022
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Benadryl is a medication most commonly used to treat allergies in humans. However, it can also be used to treat various other conditions, including motion sickness, cold symptoms, and mild pain relief. It blocks the effects of histamine, a substance released during an allergic reaction. This relieves symptoms such as sneezing, itching, and a runny nose. It can also be given intravenously by a healthcare provider. If you are familiar with Benadryl, you probably appreciate the relief you get from it. This may make you wonder if it is an option for your dog.

Seeing your four-legged friend uncomfortable is never enjoyable, so let’s jump into everything you need to know about Benadryl for your pup!

When Should You Give Your Dog Benadryl? 

Sometimes our best friends can have allergies. If your dog is scratching more than usual or seems to be in discomfort, Benadryl may be able to help. In most cases, Benadryl is safe for dogs and can provide relief from itchiness and irritation. Sometimes dogs are too curious about a bug, resulting in a bite on their nose or mouth. Allergic reactions can cause swelling, redness, and hives. If you notice this happening to your dog, you may need to give them Benadryl. However, it’s always best to avoid caution and get professional advice before giving your dog any medication.

What Are the Risks and Side Effects?

Benadryl doesn’t have any severe side effects. A few effects to be aware of Benadryl for dogs may include dry mouth, increased thirst, and urination. Other side effects may include vomiting, diarrhea, constipation, drowsiness, and excitability. If these side effects persist or seem to be getting worse, it’s essential to contact a veterinarian. Most dogs will tolerate Benadryl without any problems. 

However, it’s best to be careful about your furry friend’s health. If your dog has symptoms, it’s good to talk to a vet to ensure there isn’t something more serious going on.

If your dog takes too much Benadryl, it can be fatal, and symptoms of an overdose include dilated pupils, seizures, behavioral changes, and rapid heartbeat. It is rare that a dog has an allergic reaction to the medication itself, but it is still worth mentioning. You must seek emergency care for both if you notice an allergic reaction or overdose.

Veterinarian giving a Veterinarian giving a chihuaha a pilla pill

It’s important to consult with your vet before giving your dog any medication, like Benadryl.

© Tikhonova

What Dogs Should NOT Take Benadryl? 

For most dogs, Benadryl is a safe and effective way to treat allergies. However, some health conditions can be exacerbated by Benadryl. For example, dogs with glaucoma may experience trouble urinating, and dogs with hypertension can be affected. In addition, Benadryl can adversely affect dogs with seizure disorders. More notable conditions affected by Benadryl are heart disease, lung disease, hypothyroidism, and pregnancy. It may not be an option to give your dog at all, and in the best interest of them, you should take them to expert care where a vet can help your dog. 

How Much Benadryl Can a Dog Take?

The recommended dosage for your dog is based on their weight. You can calculate the correct amount by giving them 1mg per pound. For example, you’ll provide them 20mgs of Benadryl if they weigh 20 pounds. The dose can also vary from 2-4mg per pound, but a vet should instruct you on the proper dosage. You should avoid the liquid form of Benadryl because it contains sodium. 

There are a few creative ways to give these to your pup. You can hide the pill in a pill pocket or mix it in their food. If you get the chewable kind, your dog may think it’s a treat. For dogs that are difficult to give medicine to, you can try gadgets designed to make giving them pill easier.


Dogs are our companions that need to be looked after because they can suffer from allergic reactions. If you are trying to help your dog with itchy skin or allergies, then this medication may help. It doesn’t cause severe reactions or side effects most of the time.

Remember, like people, not all dogs respond well to the same medication, so always consult a professional before starting any treatment plan. 

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The photo featured at the top of this post is © Tikhonova

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About the Author

Creepy-crawly creatures enthrall Marisa. Aside from raising caterpillars, she has a collection of spiders as pets. The brown recluse is her favorite spider of all time. They're just misunderstood. You don't have to worry about squishing the creatures as her catching, and relocating abilities can safely move stray centipedes or snakes to a new location that's not your living room.

FAQs (Frequently Asked Questions) 

Where can you get Benedryl for dogs?

Diphenhydramine, also known as Benadryl, is one of the few over-the-counter medications veterinarians frequently instruct owners to administer at home. In most stores, you can find them in the medication aisles.

Can you give the generic of Benadryl to dogs?

Yes, both contain the same ingredients but don’t give your dog the liquid version for adults as it has alcohol.

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