Benadryl for Dogs: The Do’s & Don’ts, Dosage, Side Effects, And More

Benadryl for Dogs If your dog or emotional support animal suffers from severe allergies or allergic reactions to things around them, then you know how hard it is to watch them go through that pain. However, there is a solution: Benadryl for dogs.

“What, you say?! This ‘human drug’ can be used on dogs?! I’m not sure about that…”

Benadryl is an over-the-counter drug, most commonly known as an antihistamine, and helps alleviate the symptoms that your dog may have in regards to allergies, allergic reactions, insect bites, itching, and more.

First Things First, Is Benadryl for Dogs Safe?


Benadryl contains an active ingredient called diphenhydramine that is safe for your pet to ingest, unlike other cold, sinus, and antihistamine drugs.

Its purpose is to help alleviate the symptoms of allergies, allergic reactions, anxiety, motion sickness, bites, and much more to give your dog a more relaxed and stress-free lifestyle.

As with any new medication, however, it always pays to observe your dog closely after the dosage has been given for the first hour. The reason being is that they may suffer from symptoms that occur with the medication, or it may, in fact, irritate the dog’s skin and cause their allergic reaction to get worse.

If you are unsure that Benadryl is safe for your dog to take or they have conflicting conditions, then please consult your local veterinarian before exposing them to the medication. However:

If you are a fan of natural and holistic alternatives, the next section should be of interest to you.

Alternatives to Benadryl in Treatment for Anxiety and Painful Allergies in Dogs

There can be situations where you may not be able to consider Benadryl at all.
Like most drugs, Benadryl too has common side-effects. Your dog may suffer from dry mouth, sedation, hyper salivation, rapid breathing and increased heart rate.
If you are looking for more a more holistic remedy, we advise you consider the following options:

1. Honest Paws CBD Oil for Dogs

Allergies are no fun and sometimes can be painful or just a terrible annoyance to all dogs everywhere. But CBD surely helps with that.
With Honest Paws CBD Oil for Dogs, you can help ease that pain and give them comfort without the excess pills and what not.
We know this treat can’t cure cancer or diseases, and we are not encouraging you to stop all the medicine prescribed to your dog (that’s up to your vet), but it can help them feel better and lead an easier life (in all seasons) like all doggies should.
This fast-acting, highly absorbing full spectrum CBD Oil is great to be given directly to your pet.

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Honest Paws CBD Oil For Dogs$39.95
Honest Paws CBD Oil for Dogs features 100% Full Spectrum CBD Oil, straight from the sun-grown Colorado hemp farms. Available in 125, 250 and 500 mg potency solutions.

2. Honest Paws Restore CBD Dog Treats

Honest Paws makes the absolute best CBD dog treats, and better yet, it has a treat pack formulated specifically for allergic dogs called the ‘RESTORE’.
The Honest Paws RESTORE CBD Dog Treat is rich in Omega 6 and fatty acids that are perfect for your irritated dog’s dry, itchy skin. It is made with. 100% pure hemp oil and coconut oil.

Rated 5.00/5.00 by Certapet
Honest Paws RESTORE Coconut Flavored CBD Dog Treats$24.95
Restore CBD Dog Treats are rich in Omega 6 and fatty acids and perfect for your irritated dog's dry, itchy skin. Made with 100% Pure CBD Oil & Luscious Coconut Oil, our treats contain only the best, all-natural ingredients.

3. Vets Preferred Premium Wild Alaskan Salmon Oil

Salmon oil’s great for dogs, and Vets Preferred Premium Wild Alaskan Salmon Oil is the best of them all. Using salmon oil regularly helps relieve dry and itchy skin and moisturizes and soothes your pet’s skin from inside out.
This may be ideal for you if you dog is prone to suffering from seasonal allergies.

Rated 5.00/5.00 by Certapet
Vets Preferred Wild Alaskan Salmon Oil$19.95
Vets Preferred Wild Alaskan Salmon Oil is made from only non-farmed, freshly-caught fish from the pristine Alaskan waters. Their proprietary process creates the most pure, refined product possible (99.5%).

Diphenhydramine: Benadryl’s Most Active Ingredient

Diphenhydramine is an active ingredient that is found in Benadryl. It acts as an antihistamine that reduces the effects of chemical histamine that is found in your dog’s body.

Diphenhydramine works to reduce and target runny noses, skin rashes, sneezing, watery eyes, itching, allergic reactions, motion sickness, and other allergy symptoms.

It also helps to induce sleep to give your pet some relief at night and is one of the reasons why it is prescribed a lot to help your dog with anxiety and the symptoms that come with it.

Benadryl for Dogs: Purposes in Detail

Benadryl for dogs is a medication that helps to alleviate mild-to-moderate allergies in your dog. The active ingredient of diphenhydramine targets a range of different conditions and symptoms that your pet may be suffering.

These include:

Allergies + Common Cold for dogs

Diphenhydramine’s purpose is to eliminate allergy symptoms that your dog may be suffering. These can include:

  • Hives
  • Itching
  • Coughing
  • Sneezing
  • Swelling + inflammation
  • Redness
  • A runny nose + eyes


If your dog has been bitten by something that has caused the area to swell up or inflame, then Benadryl can help alleviate that. Diphenhydramine is also useful if your dog is experiencing an anaphylactic reaction from the bite as it targets the chemical reaction that causes this to happen.


One of the side effects of giving your dog Benadryl is drowsiness. This is because of the active ingredient of diphenhydramine and can be used for dogs that suffer from anxiety as it helps to calm them.

Other Purposes

Benadryl is an all-around type of medication and can be also used for a number of different conditions and symptoms. If your dog suffers from motion sickness during car and plane rides, Benadryl can help to alleviate that.

It is also used as therapy medication to other conditions such as tumors. Benadryl has been known to help mitigate the effects of the massive histamine release that is caused by mast cell degranulation. In some cases, veterinarians can also prescribe diphenhydramine to help treat heartworm.

how much benadryl can i give my dog

Side Effects of Benadryl for Dogs

As with all types of drugs, there are side effects and symptoms associated with using Benadryl for dogs. It always pays to check with your local veterinarian or clinic before introducing the drug to your dog, and what dosage you should give them.

Before we cover the side effects and negative symptoms of Benadryl, if your dog has any of these conditions then check with your vet before you proceed:

  • Heart failure
  • Angle-closure glaucoma
  • Bladder neck obstruction
  • Allergic lung disease
  • Prostatic hypertrophy
  • Seizures
  • Pregnancy

Once you have established if your dog has any of these conditions and have consulted a vet, the side effects and symptoms of using Benadryl for dogs can be broken down into two categories:

Common Side Effects + Symptoms

  • Dry mouth
  • Urinary retention
  • Sedation
  • Hypersalivation
  • Rapid breathing
  • Increased heart rate

Rare Side Effects + Symptoms

  • Vomiting
  • Diarrhea
  • Increased appetite
  • Decreased appetite

Monitor your dog closely for the first 1-5 hours after exposure to Benadryl, as this is when most side effects and symptoms will occur.

Benadryl Dosage for Dogs

The dosage of Benadryl you should give your pet will depend on its size. The easiest way to achieve this is to speak to your local veterinarian or following the guidelines of the chart below.



30lbs or smaller

10mg per dose

30 – 50lbs

25 mg per dose

50lbs or over

50mg per dose

For a more accurate dosage of the medication, you can use the formula – 1mg of Benadryl x 1lb of body weight.

The amount of times you can give the medication to your pet is typically around 3 times a day, 8 hours apart. However, to be sure that is correct for your dog, please consult a vet.

Beware of Over-Dosage and Allergic Reactions

benadryl dosage for dogs

Although Benadryl is safe to give to your dog, over-consumption and allergic reactions can still occur.

When a dog overdoses on Benadryl, signs will include a hyper-excitability of the dog’s central nervous system and can be fatal if not treated immediately by a veterinarian. Other symptoms of an overdose include:

  • Dilated pupils
  • Seizures
  • Rapid heart rate
  • Agitation
  • Constipation

In terms of an allergic reaction, you should take your dog immediately to the vet also. As Benadryl is a drug that is used to treat allergies to pets as well as humans, the thing to keep an eye out for is if your dog’s allergies seem to worsen upon exposure to Benadryl.

The Dos & Don’ts of Benadryl for Dogs

When it comes to giving Benadryl to your pet, there is a simple couple of dos and don’ts to apply when using the medication.

The Dos

  • Always test the drug firstnever give your dog the full dosage of Benadryl straight away. Try giving them a small amount and wait for a few hours. Watch to see how your dog reacts and if they have any side effects or symptoms.
  • Make sure your pet has a full stomach one of the symptoms of Benadryl can be nausea and a lack of appetite, so many sure that before you give your dog a dosage of the drug they have a nice full tummy.
  • Trick them and break up the tablets in food most dogs will be inclined to refuse a tablet. That is why it’s a good idea to break it up and put in in your pet’s food. They’ll never see it coming and it also makes sure they are still eating!
  • Consult a veterinarian if you are unsure whether or not you should give the medication to your dog, then it doesn’t hurt to ask a vet just to be sure.

The Don’ts

  • Give the medication to your puppy without consulting a veterinarianpuppies are like little human babies, and like them, there are some medications they can’t have. It pays to get that checked out before you go ahead.
  • Give your dog cold/sinus medications diphenhydramine is an active ingredient that is safe for your pet, however, many of the other cold and sinus medications or ingredients aren’t. Make you’re the label ONLY has diphenhydramine and nothing else.
  • Avoid liquid Benadryl as this is an over-the-counter antihistamine, it may come in the form of liquid. Make sure to avoid this as Benadryl liquid has a high concentration of alcohol content which is unsafe for your pet.
  • Do not exceed recommended dosage this can result in your pet overdosing on the medication which can have fatal side effects.

Benadryl is completely safe for your pet and can help reduce the stress and pain that comes with having allergies, anxiety, bites, and more. But again, if you are considering an alternative, we strongly recommend using Honest Paws CBD oil and CBD dog treats.

As diphenhydramine is an active ingredient that targets all those nasty symptoms your dog experiences, it is a reliable medication to give your dog when needed.

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