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Black pug sitting on the floor looking right at the camera - Is Benadryl Safe for Dogs?

Is Benadryl Safe For Dogs?

For many years, dog owners have considered Benadryl a bit of a cure-all. If your dog is…

Itchy — Benadryl

Anxious — Benadryl

Carsick — Benadryl

A little too hyper — Benadryl

Looking at you the wrong way — Benadryl

You get the point.

While Benadryl can, in fact, help with many of these issues (except maybe the side-eye), it’s not a cure-all for everything — and as with all medications, you shouldn’t play amateur pharmacist with Fido. 💊

Is Human Benadryl safe for dogs or not?

The answer is: maybe!

In general, Benadryl is considered safe for dogs, but — and this is a gigantic, Tom Green-style but — you must consult your vet first.

Why? Because with medications, there are many factors to consider:

  • Your dog’s age
  • Their weight
  • Their current health conditions
  • Any other medications they’re on

All of these factors impact whether your dog can have Benadryl, and what the proper dosage will be.

And when’s the best time to figure out if your dog can have Benadryl, and how much Benadryl can I give my dog?

Before they need it!

Ask anyone who answers the phone at a vet clinic and they’ll tell you there are at least a few calls every week asking about Benadryl. (Usually from a frantic pet parent whose dog just dove headfirst into a pollen-filled field of wildflowers, got stung by a bee, or tried to make friends with a danger noodle. 🐍)

While it's obviously a great idea to call your vet clinic when your dog is having any health issue, it’s an even better idea to discuss these things ahead of time so you can be prepared! After having this conversation, savvy dog owners opt to keep Benadryl in their pet first aid kit just in case.

To help you know what to ask, let’s take a deep dive into what exactly Benadryl is, what it’s used for, and why you should keep some on hand if your vet gives the OK.

What is Benadryl?

Benadryl is the brand name for diphenhydramine, a popular over-the-counter antihistamine. Humans have used it for decades to lessen our unpleasant allergy symptoms. 🤧

Diphenhydramine works by reducing histamines — those pesky little chemicals released by your immune system to combat invaders like allergens. Histamines can cause all sorts of inflammatory responses, such as hives, itching, sneezing, runny nose, and watery eyes.

Since Benadryl (diphenhydramine) is a human medication, any use in dogs is what’s known as “off-label” or “extra-label”. This type of use is very common in veterinary medicine, and it’s another reason it's so important to consult your vet before giving Benadryl or any over-the-counter medication.

pink pills are shaped in a question mark

What effect does Benadryl have on dogs?

Benadryl can treat a wide variety of conditions, mostly allergy-related — including seasonal allergies, environmental allergies, and allergic reactions or anaphylaxis to insect bites and bee stings. 🐝

Historically, Benadryl has also been used for motion sickness and anxiety, especially related to car rides. Nowadays, there are lots of other options and while antihistamines are still used for these ailments, they might not always be the first thing your vet recommends.

For dogs that are known as “vaccine reactors,” Benadryl can also be used as a pre-treatment prior to administering vaccines.

Benadryl is also used in the treatment of mast cell tumors, a type of cancer that is tied to the body’s immune response and can cause the release of histamines.

Occasionally, your veterinarian may also prescribe Benadryl for other conditions, or in conjunction with other medications or treatments.

Is all Benadryl Safe for Dogs?

Since Benadryl is a human medication, you may find different variations of it on the market, including some that can be dangerous for dogs!

Whenever giving your dog Benadryl, you’ll want to make sure it’s just standard Benadryl, as in *just* diphenhydramine.

Steer clear of any versions of Benadryl “Plus,” or combination antihistamines formulated for additional ailments like congestion, cough, or headache. Whether you’re shopping brand-name or generic, the same goes.

These forms of Benadryl have other medications mixed in, like acetaminophen, phenylephrine, or other ingredients that can be toxic to dogs. You’ll also want to be cautious with flavored forms of Benadryl that may contain alcohol, artificial sweeteners like xylitol, and other additives that can be deadly to dogs. 🚫

While not specific to the Benadryl brand, you can also get diphenhydramine specifically for dogs, sometimes even formulated in chicken- or beef-flavored chewables! These are typically available through pet pharmacies by prescription from your vet.

Benadryl for Dogs - Side effects to watch for

Does Benadryl make dogs sleep? Can I give my dog Benadryl for itching? Like all drugs, Benadryl has the potential to cause side effects, especially if an improper dose (AKA too much) is given.

While most dogs will only experience a mild sedative effect, kinda like they had one too many mimosas at brunch, some can experience more severe side effects.

Potential side effects of Benadryl overdose in dogs can include:

  • Drowsiness
  • Disorientation
  • Vomiting
  • Diarrhea
  • Slowed breathing
  • Seizures
  • Hyperactivity
  • Agitation

If your dog experiences any of these adverse effects of Benadryl, be sure to call your vet!

Dog sitting on chair looking on while human hands are on a laptop

Potential contraindications of Benadryl in dogs

Benadryl is mostly well-tolerated in average, healthy dogs. However, there are certain instances when Benadryl might be contraindicated — a fancy way to say this medication is a no-go for your four-legged friend. 🙅

Potential contraindications of Benadryl in dogs can include:

  • Heart conditions
  • Liver disease
  • Seizures
  • Glaucoma
  • High blood pressure
  • Urinary problems
  • Chronic obstructive pulmonary disease (COPD)
  • Hypothyroidism

Dogs that are taking other antihistamines, MAOI inhibitors, and certain other drugs can also have contraindications to Benadryl.

Very young puppies, geriatric dogs, and dogs that are pregnant or lactating can ALSO have contraindications to Benadryl.

Always alert your vet of any health conditions your dog may have before starting a new medication or supplement.

Benadryl for Dogs Dosage Chart


While your dog’s vet can prescribe the proper dosage of Benadryl for your pup, 1 milligram per pound is often the easiest way to calculate a safe and effective dose. How much Benadryl to give a 50 lb dog would depend what dose you'd want to give them. On the low end, give them 45mg but a higher dose would be around 90mg. But again, always talk to your vet first before administering the dose.

Benadryl Dosage Chart for Dogs

(We swiped this handy Benadryl dosing chart from Kingsdale Animal Hospital. Thanks, Kingsdale.)


If you’re giving a liquid version of Benadryl or diphenhydramine, it can be a bit harder to calculate and measure the proper dose.

In addition to talking to your vet (in case we haven’t emphasized that enough yet 😉), an online calculator from a reputable veterinary source, such as the Diphenhydramine Dosage Calculator, can be helpful.

Are there alternatives to Benadryl for dogs?

Yes, but it largely depends on what condition you’re using Benadryl to treat.

For dogs experiencing itchy skin or allergies — one of the most common reasons Benadryl is given — there are a ton of options. Everything from other types of medications and allergy shots, to food and lifestyle changes, to fish oil supplements.

If your dog is having symptoms of allergies, have them checked out by your veterinarian, because there can be a mountain of potential causes.

And while a quality fish oil supplement can do wonders for dry, itchy, or inflamed skin, it won’t do as much for fire ant bites as Benadryl.

When it comes to anxiety, there are also many different causes and treatment options, so again — it’s important to talk to your vet before you start medicating your pet or seeking out alternative treatments.

Bottom line: every treatment has its place, so what you give your dog will depend on the root cause of their issue.

Supporting your dog’s skin and coat

While it’s super duper important to get to the bottom of any allergies or skin issues with your vet, and while having some Benadryl on hand can be great for emergencies, you can still be proactive with your dog’s skin and coat health.

I want to be reincarnated as this dog.

Ways to help support your dog’s skin and coat

  • Feed a balanced, nutritionally sound diet — Nutritional deficiencies can lead to skin and coat problems (among other scary things). Ensure your dog is getting a complete and balanced diet that is adequate for their age and lifestyle. If you feed homemade, raw, vegan, or other non-standard diets, talk to your vet to ensure they are getting proper nutrition, and fill in any gaps with a quality dog multivitamin.
  • Parasite prevention — Staying on top of your dog’s parasite prevention regimen can go a long way in preventing an itchy situation. If your dog isn’t already on preventatives, talk to your vet ASAP.
  • Regular bathing and brushing — Bathing and grooming needs can vary based on your pet’s coat type and lifestyle, but keeping their coat clean and unmatted will help keep their skin healthy. If your dog has dry, itchy skin or a specific dermatological condition, your vet may recommend a medicated shampoo.
  • Omega-3 fatty acid supplementation — Many dogs can benefit from the addition of omega-3 fatty acids to their diet. A high-quality fish oil supplement can help soothe and nourish dry itchy skin, reduce inflammation, and promote a healthy coat.
  • Lots of belly rubs — Ok…we know what you’re thinking…no, your dog didn’t write this! Routine belly rubs are a great time to “inspect” your pup for any signs of fleas, ticks, dry skin, hot spots, or any other skin woes. Plus, it makes for a happier pup — it’s a win-win!

There you have it. Everything you wanted to know about Benadryl… and maybe some things you didn’t.

In case we didn’t say it enough already: Talk to your vet before giving your dog Benadryl!

We love dogs, so we’re here to educate and help keep your pups safe and happy. (And if you need help picking out a quality fish oil for them, we can help with that too.)

Next article Best Supplements for Arthritis in Senior Dogs

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