Ultimate Dog

By Kristin Hitchcock - Reading Time: 10 minutes

Benadryl for Dogs: Treating Your Dog’s Allergies

Nobody likes allergies – including our furry friends. Just like humans, dogs can get allergies. When they do, you might be wondering if you can give them Benadryl, the same medication you likely take when you get allergies. 

The short answer is yes. Dogs can take Benadryl when given at the proper dosage. It works on dogs just like it works on humans. However, the long answer is a little more complicated.

Benadryl is not suitable for treating all types of allergies in dogs, and it is not necessarily the best option for your canine.

To figure out the best way to combat your dog’s allergies, let’s start by taking a look at what Benadryl for dogs is.

What is Benadryl for Dogs?

Benadryl for dogs is the same as the Benadryl used for humans. It is the brand name for the ingredient diphenhydramine HCl. As you can imagine, it is popularly called Benadryl because not very many people can properly spell or pronounce “diphenhydramine.”

Benadryl is an antihistamine, which means it blocks the H1 receptors on our blood vessels. These receptors are the primary cause of allergic reactions. You block the receptors; you stop the allergic reaction.

Benadryl is categorized as a first-generation antihistamine. This classification means that Benadryl crosses the blood-brain barrier. This barrier is the protective coating that prevents potentially harmful substances from entering the brain. Because Benadryl can pass through this barrier, it is quite effective.

However, by passing this barrier, Benadryl can directly affect the brain.

Is Benadryl Safe for Dogs?

Benadryl is considered to be a relatively safe medication for dogs, especially those that experience acute allergies.

It is important to note, though, that Benadryl is not cleared by the FDA for use in dogs or cats. While it can be used safely in most cases for your dog, there are no official dosing guidelines.

Furthermore, there is no dog-specific Benadryl. Instead, your furry friend will have to take the same over-the-counter medication that you take. This can create some problems because not all forms of Benadryl are safe for dogs.

For example, time-release capsules are not safe for canines. These capsules interact with dogs differently than humans. They may become chewed and break open, delivering too much medication at once.

While Benadryl typically refers to diphenhydramine HCl only, it can contain other active ingredients as well. These ingredients may or may not be safe for your dog. It is essential to check that the Benadryl you plan on using contains only diphenhydramine HCl. This information is located on the information panel.

Benadryl for Dogs Side Effects

Like most medications, Benadryl can cause quite a few side effects.

The most common side effects include sedation and dry mouth — many dogs who are given Benadryl experience these problems. Urinary retention, hypersalivation, increased heart rate, and rapid breathing are also common. While none of these side effects are particularly severe, you should consider whether or not your dog’s current symptoms are severe enough to worth risking these side effects before giving Benadryl.

More severe and rare side effects are also possible, such as diarrhea, vomiting, and appetite changes. These side effects are particularly serious in older and younger canines.

Dogs can also overdose on Benadryl. This is not always caused by giving a dog too much medication. Instead, it can also be caused by giving your dog the wrong kind of Benadryl, such as the time-release capsules.

Signs of an overdose include hyperactivity, depression, hypersalivation, and changes in heart rate.

Using Benadryl for Dogs

There are various uses for Benadryl for canines. The treatment of allergies is most common. However, treating anxiety and insomnia using Benadryl is not unheard of.

Benadryl might not be the best option for your canine, depending on what you want to treat. Before you decide whether or not to give your dog Benadryl, let’s look at what it can treat effectively.

Benadryl for Dog Allergies

While dogs do get allergies, they often do not look like human allergies at all. Instead, dog allergies typically produce skin irritation, which can result in lots of scratching and biting. Respiratory symptoms, like sneezing and coughing, can also occur but are much rarer.

There are two main types of allergies in dogs: acute allergies and chronic allergies.

Acute allergies are short-term only. They can be caused by any number of things, including specific foods, insect bites, environmental irritants, and pollen. Benadryl works very well for mild to moderate acute allergies.

You should remove the underlying cause of your dog’s allergies if possible. In the meantime, Benadryl can help control your dog’s symptoms.

If your dog is experiencing extreme face swelling or difficulty breathing, it is essential to contact your vet instead of trying to treat the reaction at home.

Benadryl is also somewhat capable of treating anaphylaxis in dogs. In emergencies, it can be used to stop a deadly allergic reaction.

Chronic allergies are much rarer than acute allergies. They occur when a dog is allergic to many different substances or one prevalent substance. If a dog is allergic to many types of proteins, for example, it can be nearly impossible to clear their diet of all allergens. You might also not know what is causing your dog’s allergies in the first place, which can make removing the underlying cause very difficult.

Benadryl is not very good at treating chronic allergies for a couple of different reasons. Firstly, it has to be given multiple times a day to work consistently. Secondly, the likelihood of side effects occurring goes up with extended use. Your dog probably does not want to spend the rest of their life feeling drowsy.

Luckily, there are some natural, gentler options for treating dog allergies, which we will discuss later in this article.

Benadryl for Dogs Anxiety

Because of Benadryl’s sedative effects, you might consider giving it to your dog to help with their anxiety.

However, this is not usually the best option. Benadryl does not make every dog sleepy. Some dogs might even become hyperactive after taking Benadryl. The last thing you want is for your anxious dog to become hyperactive and more anxious, so it is often a better idea to choose a different solution for your pets’ anxiety.

Luckily, there are many different natural remedies for dog anxiety out there. Many of these remedies work better and more consistently than Benadryl.

Benadryl for Dogs Sleep

If your dog is not sleeping well, it can be tempting to try and knock them out with Benadryl. But, as we’ve discussed, Benadryl does not make every dog sleepy and can even make some hyperactive.

Furthermore, if your dog is not sleeping well, there is probably a reason. Speaking to your vet can help you figure out if there is an underlying cause of your dog’s insomnia. Many remedies and medications are much more effective at producing restful sleep than Benadryl.

If you need to make your dog sleepy for a short period, like during a trip, for example, other medications work more effectively and safely than Benadryl. You can speak to your veterinarian about possible sleeping prescriptions for your canine.

Benadryl for Dogs Itching

If your dog is continually itching, it is likely an allergic reaction.

As we discussed in the allergy section, Benadryl is useful for treating acute, short-term allergies. If your dog is reacting to a flea bite, Benadryl can calm the reaction down while you work to remove the fleas.

However, if your dog is itching for days and days, it is probably time to find a different treatment option. Working with your vet to determine the cause of the allergies is often helpful, as is trying natural supplements and remedies.

Of course, you should also speak to your vet to ensure that the itching is allergies and not a different medical condition.

Safe Dose of Benadryl for Dogs

If you decide that Benadryl is the right option for your dog, it is essential to stick to the correct dosage. Giving your dog too much can result in an overdose.

The amount of Benadryl largely depends on your dog’s weight. Generally, it is recommended to give your dog 2-4 mg of Children’s Liquid Benadryl for every kilogram of body weight. That’s approximately 1 mg per 1 pound of bodyweight.

You should always start with the lowest dose and work your way up as needed. Benadryl takes about 30 minutes to work.

It is always a good idea to work with your vet when administering a new medication to your dog. Your dog’s current drugs, health conditions, and age can affect their Benadryl dosage.

Children’s Benadryl for Dogs

The type of Benadryl you give your dog also matters. Liquid Children’s Benadryl is the safest option for most dogs. It is the easiest to give and does not contain many of the extra ingredients other types of Benadryl often do, like alcohol.

Children’s Benadryl tablets can also be used for tiny dogs. Dosage for tablets is different than liquid and depends on the exact tablets you have. We recommend working with your vet when giving tablets as the concentration varies quite a bit.

Alternatives to Benadryl for Dogs

Due to the likelihood of side effects and ineffectiveness of treating anxiety and sleep disorders, it is worth considering a natural option to Benadryl for your dog.

To help you make the most informed choice possible, here are some of the most common alternatives to Benadryl.

Natural Remedies for Dog Allergies

Allergies occur when a dog’s immune system is not working correctly and reacts to something that isn’t harmful, like chicken protein, for example.

Supporting your dog’s immune system with high-quality food and specially formulated supplement can decrease their allergy symptoms.

Topical herbal treatments can also be useful for treating excessive itchiness and inflamed skin. Oat baths, aloe vera, and coconut oil are all useful for this purpose.

Depending on the cause of the dog’s allergies, you should also minimize his exposure to fleas. Flea bites can trigger allergies in some dogs. Even if your dog does not have live fleas on them, they can still get bitten when outside or around other dogs. Sometimes fleas can also live in your carpet or furniture.

Some dogs develop an allergic reaction to allergens in the air. Because of this, improving your home’s air quality with a filter can be useful.

You can also try switching your canine’s food. Dogs can develop food intolerances no matter their age. Even if they’ve been on the same diet their whole life, it might be the cause of their symptoms.

Natural Remedies for Anxiety in Dogs

There are many natural remedies for dogs that are more effective and safer than using Benadryl.

CBD oil, chamomile, and valerian can all be helpful in cases where a specific event triggers your dog's anxiety.

Pheromone dispensers and pressure vests can also be helpful.

Natural Remedies for Insomnia in Dogs

Many of the natural remedies for dog anxiety are also helpful for insomnia. Often, a dog cannot fall asleep because they are anxious. In these cases, treating the anxiety usually fixes insomnia.

Massage therapy, more exercise time, and melatonin can also be helpful in many cases.

Should I give my dog Benadryl?

Whether or not you use Benadryl to treat your canine is up to you and your veterinarian. Benadryl is excellent at treating short-term allergies in dogs when used correctly.

However, Benadryl is not always the best option when treating long-term allergies, sleep disorders, and anxiety. In these cases, it is often best to explore other options before deciding to give your dog Benadryl. 


Harvey, R. “Food allergy and dietary intolerance in dogs: A report of 25 cases.”Journal of Small Animal Practice. April 1993.

Fray, Timothy. “A Combination of Aloe Vera, Curcumin, Vitamin C, and Taurine Increases Canine Fibroblast Migration and Decreases Tritiated Water Diffusion across Canine Keratinocytes In Vitro.” The Journal of Nutrition. August 2004. 

Shipstone, Miachael. “Antihistamines for Integumentary Disease”. Merck Manual.

Wells, J. “Modification of Anaphylaxis by Benadryl.” Journal of Experimental Biology and Medicine. Frebruary 1946.

Khan, Safdar. “Cold and Couth Medications (Toxicity).” Merck Manual. 

Kristin Hitchcock

Kristin Hitchcock was born and raised in Tennessee and currently lives there with her husband and daughter. She is passionate about helping pet parents create an enriching and fulfilling life for their canines by providing up to date, actionable insights. She currently owns two dogs, three cats, two lizards, and a bird. 

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