Giving Dogs Benadryl: Safety, Dosage & Side Effects

Can you give your dog Benadryl? Benadryl may be given to dogs at a dosage of 1mg to 1lb of weight. Always check the package for tablet mg and ensure you are using Benadryl or antihistamine tablets with diphenhydramine as the active ingredient.

If you think your dog may suffer from occasional allergies, benadryl may help provide your dog with some much needed relief!

Just like their humans, dogs can also suffer from the inconvenience and discomfort of allergies. They may be chronic or acute and it’s important to recognize the signs of an allergy attack in your pup. Benadryl can help relieve symptoms, but it needs to be administered in a safe dose.

Infographic for Benadryl For Dogs with dosage

Common uses for Benadryl in dogs

Benadryl can be used for many reasons to treat dogs. Here are our top 11 common uses:

  1. ​Itchy or irritated skin
  2. Nausea
  3. Insmonia
  4. Anxiety
  5. Insect or flea bites
  6. Bee stings
  7. Swelling or inflamation
  8. Sneezing or coughing
  9. Stuffy or runny nose
  10. Hives
  11. Allergies

How do allergy symptoms manifest themselves in a dog?

Dogs can have very diverse allergy symptoms, so it is vital to know what the signs are and how to differentiate them from other potential health problems. When allergies strike, dogs may experience one or more of the following:

  • Itchy, red, damp or scabby skin

  • Scratching

  • Itchy, runny eyes

  • Itchy back or tail

  • Itchy ears and/or ear infections

  • Sneezing

  • Vomiting and/or diarrhea

  • Snoring

  • Paw chewing/swollen paws

  • Increased licking

What are the main causes of allergies in dogs?

Like humans, dogs can be allergic to many different things, and it may be difficult to pinpoint what is causing the reaction. Here are the most common allergens among your canine friends:

  • Shampoos and perfumes

  • Cleaning products

  • Certain fabrics or materials

  • Insect and flea bites

  • Grass, pollen or other plants

  • Certain food ingredients, like wheat, for example

  • Feathers

  • Mold and mildew

What is Benadryl?

Benadryl is a brand name antihistamine drug that prevents the natural effects of histamine in the body. These typically produce effects such as sneezing, itching, watery eyes, and runny nose.

Benadryl is used to treat these symptoms through an active ingredient called diphenhydramine. While Benadryl is the brand name for this product many stores will carry other brands of this drug.​ It is important to remember though you do not want to purchase any drug containing Pseudoephedrine or Acetaminophen. These can be harmful to dogs.

These drugs can be purchased over the counter in capsule, pill, liquid and cream form. Always check the label to view its active ingredients and dosage.

Benadryl dosage for dogs

How does Benadryl work?

This medication works by stopping the histamine reactions that your body produces when it has an allergic reaction or cold. Once your dog is exposed to an allergy the histamine travels to the various parts of the body such as eyes and nose. This causes the blood vessels to expand and widen causing swelling and inflammation.

Benadryl does not cure or shorten the length of a cold but rather helps to relieve the effects. The drug attacks the histamine in the body and reduces the symptoms.

Things to consider before giving your dog Benadryl

You should always consult your veterinarian if you have any questions or before administering medication your unfamiliar with. A few things you may want to consider before giving your dog any benadryl are.

  1. Ensure that your dog is not on any other medications that may interact negatively with Benadryl
  2. Make sure the active ingredient is Diphenhydramine​ 
  3. Do not use liquid Benadryl, as it contains higher alcohol levels.
  4. Do not use time release tablets
  5. Use children's Benadryl for smaller dogs

How much Benadryl can I give my dog to relieve his allergies?

If your pup is showing signs of an allergy, Benadryl can definitely help ease the symptoms and make your dog, and yourself, feel better. Benadryl is an antihistamine that is safe for dogs when given appropriately, using proper dosage and time intervals.

The accepted dosage of Benadryl for a dog is 1 mg per pound of body weight and can be administered 2-3 times a day. Most pharmacy tablets are 25 mg, which is the perfect size for a 25 pound dog. If the dog weighs 50 pounds, he would get 2 tablets at a time. Tablets may also easily be cut in half. It is important to stick with Benadryl, and not use another brand, since some of these also contain other medicinal ingredients not suited for dogs.

Benadryl Dosage Chart for Dogs

How to Give Your Dog Benedryl

Side Effects of Benedryl

Common side effects for Benadryl in dogs include:

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

Should any of the aforementioned side effects occur you should closely monitor your dogs behavior while using Benadryl. If you notice any additional effects or if your dogs reaction should worsen you should contact your veterinarian.

When should I contact a veterinarian?

When you first notice that your dog seems to be reacting to something, you may want to make an appointment with your veterinarian to try to figure out what there allergic to. If you already know that your dog has a specific allergy, Benadryl is a safe option, and is usually always recommended by veterinarians. However, allergies that are acute, come on suddenly, leave a lot of swelling and cause difficulty breathing, can be extremely serious. Don’t wait; take your dog immediately to his veterinarian.


Allergies are an inconvenient and uncomfortable part of many people’s and dog’s lives. Fortunately, we have medication that can ease the symptoms of mild allergies when they strike. It is helpful to know what allergens are specifically causing the attacks, so we can avoid them. Unfortunately, they can sometimes be difficult to pinpoint. A severe allergy attack can be a serious condition requiring immediate medical attention from a veterinarian, and the others, we just learn to live with by adapting our dogs’ daily rituals and routines.


About the author

Melanie Fox

Hi there, I'm Melanie Fox, editor at Beloved Bark. We look to provide people with the knowledge and tools to make smarter, more educated choices for their dogs. We have made it our mission to inform our followers with expert advice and recommendations, that will make a difference in your dog's life.

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