Benadryl for Dogs: Uses, Dosage, Side Effects, and More | All You Need to Know

Benadryl for Dogs

Benadryl for Dogs: How it Works, How Much to Give, Possible Risks, and More

Benadryl is an over-the-counter medication commonly used to treat allergies in humans, and pet owners may be familiar with it. Did you know, however, that dogs can also benefit from taking Benadryl? In this article, we’ll examine Benadryl for dogs in greater detail, covering its applications, dosing, and potential effects.

Benadryl… what is it?

Benadryl, or diphenhydramine, is an antihistamine used to treat symptoms of allergies and allergic reactions like itchiness and hives. It alleviates allergies by reducing the body’s production of histamine.

Benadryl: Safe for Fido?

Benadryl is safe for dogs, but it should only be given to them if prescribed by a vet. When used properly, Benadryl is safe for dogs, but it can be harmful if the dosage is off or if your dog has a preexisting condition.

Why Do Dogs Take Benadryl?

Benadryl has many canine applications, such as:

  • Benadryl is effective in treating itching, swelling, and hives caused by canine allergies.
  • If your dog suffers from motion sickness while riding in the car or on a plane, give him some Benadryl.
  • Anxiety: Benadryl’s sedative properties make it a useful tool for treating canine fretfulness.
  • Benadryl may be prescribed by your vet to help your dog get some shut-eye if he or she is experiencing insomnia.

Canine Benadryl Dosage

Your dog’s weight and health status will determine how much Benadryl to give him. Benadryl should be administered at a rate of 1 milligram per kilogram of body weight. This, however, may vary depending on the specific needs of your dog, so it’s best to check with your vet first.

Benadryl Dog Adverse Reactions

When used properly, Benadryl is generally safe for dogs. However, there are a few potential side effects to keep in mind.

  • Benadryl can cause drowsiness in dogs, which can be a plus if used to treat anxiety or nervousness but a negative otherwise.
  • Benadryl’s side effect of dry mouth in dogs can be unpleasant and lead to excessive hydration needs.
  • Dogs taking Benadryl may experience urinary retention, which can lead to urinary tract infections and other symptoms.
  • Although it is uncommon, Benadryl can cause an allergic reaction in some dogs. These dogs may experience hives, swelling, and trouble breathing.

Use of Benadryl in Dogs: Caution Is Advisable

There are a few things to keep in mind before giving your dog Benadryl:

  • Talk to Your Vet: Before giving Benadryl to your dog, or any other medication, it’s important to talk to your vet about the proper dosage and any risks involved.
  • While Benadryl has been shown to be safe for dogs, it is still important to keep an eye out for any negative reactions or side effects in your pet.
  • Disorientation, sluggishness, and fatigue.
  • Do not give to certain dog breeds if you have any doubt about their sensitivity to Benadryl’s effects; for example, Collies and Australian Shepherds.
  • In the absence of veterinary advice, Benadryl should not be given to dogs suffering from glaucoma, heart disease, high blood pressure, or hyperthyroidism.

Benadryl Dosage for Dogs

There are a few things to keep in mind if your vet has suggested giving Benadryl to your dog.

  • It is often easier to administer liquid Benadryl or chewable tablets to dogs than traditional pills.
  • Try disguising the pill in your dog’s regular meal or a special treat to make it more palatable.
  • Carefully adhere to your vet’s recommendations for the dosage and frequency of Benadryl administration for your dog.
  • Be Aware of Possible Side Effects: Keep an eye out for any signs of drowsiness, lethargy, or lack of coordination in your dog.


It is important to use Benadryl under the guidance of a veterinarian, but the medication can be helpful for dogs with allergies, motion sickness, anxiety, or insomnia. Before administering any medication to your dog, you should always check with your veterinarian to determine the appropriate dosage and procedure.


Will giving my dog Benadryl make him hyper?
While Benadryl is more likely to make dogs sleepy or lethargic, it has the potential to have the opposite effect and make dogs hyperactive in extremely unusual circumstances.

Can I treat my dog’s itching with Benadryl?
Canine itching due to allergies or other skin conditions can be treated with Benadryl. However, before giving anything to your pet, it’s best to talk to your vet about the safest and most effective dosage.

Can I give Benadryl to my dog if he or she gets car sick?
If your dog experiences motion sickness, you can give him Benadryl; just be sure to follow your vet’s recommendations for dosing and administration.

How long before you see results when giving a dog Benadryl?
Benadryl in dogs typically starts working within half an hour to an hour, and its effects can last for several hours.

Can I give Benadryl to my dog daily without worrying?
Benadryl is generally safe for dogs, but you shouldn’t give it to your dog every day unless your vet says it’s okay to do so.

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Jackie Brown

About the Author: Jackie Brown

Writer, editor, and pet expert Jackie Brown has spent more than 25 years following her passion for animals. She is a regular contributor to numerous pet and veterinary industry books, magazines and websites.Jackie has an extensive background in dogs and cats, particularly in purebred dogs and pedigreed cats, and is passionate about all pet topics, including veterinary and health topics, general care, nutrition, grooming, behavior, training, rescue and animal welfare, lifestyle, breeding and showing (cats as well as dogs), dog sports and activities, and the human-animal bond.