Our pets become like our children so it’s understandable that you would do just about anything to help your favorite floof when it isn’t feeling too good. You might even look to your own medicine cabinet to help. It’s understandable, but certainly not advisable in most cases.

For the most part, human medication simply isn’t designed for dogs’ bodies. The dosages are usually way off – dogs’ bodies are much smaller than our own and metabolize and use medication differently.

Sometimes, the ingredients in human medications are wildly inappropriate for canine consumption. Some medicines contain alcohol and other potentially toxic ingredients. Therefore, it’s essential that you contact a trained veterinarian rather than try to treat your pooch yourself with human meds.

There are a handful of exceptions to this rule. Like Benadryl, for example. Benadryl is a common household medication that can be safely given to dogs under certain conditions. It’s ALWAYS best to consult a vet first but here’s what we know about giving your dog Benadryl.

Stop Googling - Ask a Real Vet

What is Benadryl?

Benadryl is an over-the-counter drug (also known as diphenhydramine) that vets often require pooch-pawrents to administer at home.

It’s most commonly used to ease canine anxiety or to treat mild allergies and allergic reactions (remember that time your dog tried to eat a bee and got a swollen snout instead?). It’s essentially an antihistamine which means it blocks receptors in human and canine bodies that receive histamines.

This action helps to relieve the symptoms of allergies like itching, swelling, sneezing, and hives. It also has the added effect of causing drowsiness which can be used to calm an anxious pooch, although this isn’t its primary function.

It’s important to mention at this point that while Benadryl is well tolerated by dogs and does have its uses, it’s important to use it with caution and only at the correct dose. Therefore, you always need to reach out to a vet before using Benadryl for dogs.

Other reasons for this are that Benedryl can interact with other medications your dog might be on, or it might be contraindicated with certain health conditions. Never try to diagnose your dog yourself.

Use of Benadryl

“Can you give a dog Benadryl for anxiety?”

The most common use for Benadryl in dogs is to treat mild to moderate allergies. From seasonal allergies to food allergies and even allergic reactions to things like snake bites and bee stings, wasp stings, ant bites, and a variety of other insect bites.

Benadryl’s antihistamine action relieves the symptoms of these allergies which can include:

  • Runny nose and eyes
  • Sneezing
  • Coughing
  • Swelling
  • Skin itchiness
  • Hives
  • Redness
  • Anaphylactic reactions

Another benefit of Benadryl for dogs is that it sometimes causes drowsiness which can safely and effectively be used to treat moderate anxiety in dogs. It’s always best to treat the underlying cause of the anxiety but if you’re in a bind, Benadryl can be useful. Travel anxiety and anxiety during thunderstorms or from fireworks can also be treated using Benadryl.

Benadryl can also be effective in treating motion sickness.

Dosage of Benadryl for Dogs

“How much Benadryl can I give my dog? What is a lethal dose of Benadryl for dogs?”

While there are general guidelines for the correct dosage of Benadryl for dogs, we always recommend consulting your veterinarian first. That said, the general guideline is 2-4 milligrams per kilogram of body weight or 0.9 to 1.8 milligrams per pound given three times per day. Check out this handy Benadryl for dogs calculator.

Benadryl also comes in a variety of forms, including liquid, tablets, children’s chewable and liquid tablets, as well as time-release tablets. Tablets and children’s chewable tablets are your best options but use caution with other forms.

Time-release medications break down differently in a dog’s body so should never be used to treat dogs. A dog’s stomach can cause the time-release tablets to break down more quickly, which can cause an overdose by releasing a lethal dose of Benadryl for dogs.

Caution must also be used when opting for the liquid as this will be absorbed differently in your dog’s body. Always consult your vet before using liquid Benadryl as the dosage may need to be adjusted.

Puppies should rarely be given Benadryl without the guidance of a vet as their bodies can be very sensitive to the ingredients.

It’s very important to always check for other active ingredients and avoid giving your dog anything that contains alcohol or decongestants as these can be toxic to your dog.

Side effects and special precautions for Benadryl

“Can Benadryl make dogs hyper?”

Benadryl has few side effects and is generally well-tolerated in most dogs. There’s also a very low risk of overdose.

That said, it’s a good idea to be familiar with these potential side effects before giving your dog Benadryl. Side effects usually become apparent within the first hour or so after consumption.

Common side effects of Benadryl for dogs:

  • Drowsiness
  • Rapid breathing
  • Drooling
  • Dry mouth
  • Increased heart rate
  • Urinary retention

Rare side effects of Benadryl for dogs:

While it’s uncommon, your dog can experience an overdose of Benadryl which can be fatal. If you see any of the following symptoms or believe that your dog may be experiencing an overdose, contact your veterinarian immediately.

Similarly, if you suspect your dog is experiencing an allergic reaction to Benadryl, seek veterinary care without delay.

During pet emergencies such as overdose of medications in dogs, it can be a scary and stressful time for both your pet and yourself. Having support during these times would really help. This is where Petcube’s Pet Emergency Fund may come in.

Petcube’s Pet Emergency Fund doesn’t just offer you a financial net during pet emergencies, you also get access to a 24/7 online vet service, so you can consult with certified veterinarians anytime and anywhere. For every yearly subscription, you get upto $3000 for pet emergencies (covering upto 6 pets). All cats and dogs are welcomed regardless of age, breed, and medical history. That way, you are assured of the support that you need during critical times.

Now is the perfect time to be prepared for pet emergencies. Luckily, we are giving an exclusive 27% off on Pet Emergency Fund subscriptions as a way to say thank you, our dear readers, for your continued support. Follow this link to access the discount.

Signs of a Benadryl overdose in dogs:

  • Seizures
  • Rapid heartbeat
  • Agitation or hyperexcitability
  • Dilated pupils
  • Constipation
  • Slow or shallow breathing

When not to use Benadryl for Dogs

“Can I give a pregnant dog Benadryl?”

Certain canine health conditions can make the use of Benadryl very dangerous. Therefore, it’s essential to contact your vet before giving Benadryl to your dog.

Medical conditions which make it dangerous to give your dog Benadryl include pregnancy and nursing, glaucoma, heart conditions, and low blood pressure.

What if I don’t have Benadryl? Are there alternatives?

If your dog has allergies and you don’t have any Benadryl at home, you can also use cetirizine (Zyrtec) or loratadine (Claritin). As usual, always check with a vet first before administering any human medications to your dog. Especially if your dog has preexisting conditions or is on other medication.

Natural allergy relief can be gained by using quercetin which is a natural ingredient derived from the peels of fruits and vegetables. Not only does quercetin contain antihistamine properties, but it contains anti-inflammatory and antioxidant properties. Chat to your vet about quercetin as an allergy reliever in dogs.

CBD (cannabidiol) is another natural alternative to Benadryl. It’s derived from hemp plants and contains absolutely no psychoactive properties so there’s no chance of getting your dog high. The benefits of CBD include the relief of skin conditions, as well as itching and hives related to allergies. Dogs that experience motion sickness will also benefit from CBD, as will those suffering from anxiety, pain, or nausea.


Most human medication should never be given to dogs, with the exception of a small number of medications, including Benadryl.

Always make sure to consult with your vet before giving your dog Benadryl to ensure it’s the right solution for your pet and to ensure you’re giving the correct and appropriate dose.

While Benadryl makes a handy fallback plan in an emergency, if your dog suffers from frequent allergies or regularly experiences anxiety, it’s better to get to the source of the problem instead of relying on Benadryl to deal only with the symptoms.

Was this article helpful?

Help us make our articles even better

Yes No

Thank you for your feedback