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Benadryl Dosage for Dogs

The Benadryl Dosage Chart infographic below is an abbreviated guide.  The chart shows the most commonly accepted Benadryl dosage for dogs. 

I am not a veterinarian and I cannot prescribe or diagnose your dog.  Please do not give your dog an over-the-counter medication without checking with a licensed veterinarian first. 

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The Appropriate Benadryl Dosage for Dogs

WARNING:  Please make sure that the Benadryl used is either a tablet or capsule. The liquid form contains ingredients that can be harmful to your dog. Make sure there is no alcohol, acetaminophen, pseudoephedrine, or artificial sweeteners. Xylitol is extremely toxic for dogs.

Here is a Simple Formula For You

The generally accepted rule is to administer 1 mg per pound, two to three times daily.

Very Small Dogs (4 – 10 pounds)

The appropriate Benadryl dosage for dogs in this case would be 1/4 of a tablet. 

Small Dogs (10 – 20 pounds)

In this case, the dosage would be 1/2 tablet.

Medium Dogs (20 – 30 pounds)

A medium dog would take 1 Benadryl tablet.

Large Dogs (30 pounds and over)

The dosage rules change a little when we get to very large dogs. Types of very large dogs include: Great Dane, Mastiff, Newfoundland, St. Bernard, Great Pyrenees.

How to Administer Benadryl to Dogs

Most dogs will eat just about anything you put in front of them. However, there are those picky dogs that you have to trick.  I usually stick a tablet inside a piece of bread and that works.  Some dogs are a little smarter than mine and need different options.

Pet stores sell various types of treats that come with a hole in which to place the tablet.  Dogs are usually so happy to get treats they’ll just gobble it up in seconds without even noticing the pill.  

Benadryl Capsules 

If you are using Benadryl capsules, break one open and sprinkle it on the dog’s food, mix it with a teaspoon of peanut butter, or sprinkle on a piece of toast.  


REMINDER:  Refer to the Benadryl dosage chart before using an entire gel cap!  A small to medium dog doesn’t need as much of the medication. You might have to buy a tablet that you can cut into appropriate sizes.

Side Effects of Benadryl for Dogs

It’s always worth pointing out potential side effects. The most common side effects include dry mouth, fatigue, rapid breathing, and urinary retention.  If you’re sticking with the Benadryl dosage chart, however, most healthy dogs will not show any serious side effects.  You may not even notice the ones noted above.

You might also be interested in Putting a Dog to Sleep with Benadryl.

Disease versus Benadryl for Dogs 

Never assume that that Benadryl dosage chart is right for all dogs. In fact, your veterinarian may have very good reasons for not recommending the medicine at all. 

If your dog has any kind of chronic condition (diabetes, Cushing’s, allergies that have secondary bacterial infections, glaucoma, etc.) ask your veterinarian if Benadryl is appropriate.

If your dog hasn’t been to see the veterinarian for a while, he/she may suggest a visit.  The reason for this is so that the dog can be examined for underlying conditions. There’s a chance that your dog needs more than just Benadryl, or that the problem you thought you were treating wasn’t actually the whole picture.

You Don’t Want to Miss These TIPS:

Just because you gave your dog Benadryl safely a few years ago, doesn’t mean it’s safe now.  Remember, your dog’s health may have changed and he/she could have underlying conditions you are not aware of.

Look at the product ingredients to be sure it only contains diphenhydramine. Some Benadryl products have added ingredients.

Benadryl should not be given to your dog long-term. If your dog continues to suffer from allergies and itching, bring him/her to the veterinarian.  Aggressive itching and biting at the area can cause a bacterial infection.

Read About Lick Granulomas here!

At the end of the day, everyone wants a happy and healthy dog.  Remember that you’re not alone when it comes to health-care decision making. Always check with a licensed veterinarian before administering over-the-counter drugs designed for people or pets. The appropriate Benadryl dosage for dogs may vary according to special health considerations.  

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