Benadryl for Dogs: Use

Benadryl For Dogs: Dosage, Benefits, & Side Effects

If your dog suffers from allergies or has an allergy, the solution can be found in your medicine cabinet or your neighborhood drugstore. We’re talking about Benadryl. While other human drugs should NOT be used on our canine companions, Benadryl is safe to use with the right dosage.

What is Benadryl

Benadryl, also known by its active ingredient diphenhydramine, is an antihistamine that alleviates both human and dog allergy symptoms.

Benadryl has a variety of uses when it comes to your dog’s health. In this article, we explain how to give your dog Benadryl, the proper dosage according to body weight, and its potential side effects. We also have suggestions for natural alternatives to Benadryl.

Can I Give My Dog Benadryl? 

Yes, you can give your Benadryl safely to your dog. Veterinarians approve using Benadryl for dogs for a number of reasons. Antihistamines like Benadryl can help ease motion sickness, inflammatory and allergic reactions from insect bites and seasonal allergies.

Benadryl tablets work by blocking H1 receptors to keep histamines at bay, reducing symptoms of allergies. PetMD’s Doctor of Veterinary Medicine Jessica Vogelsang assures dog parents that the drug is “well tolerated and has a wide safety margin” for use on dogs.

Benadryl Usage for Dogs

Veterinarians recommend Benadryl – and its generic diphenhydramine – for dogs for a range of symptoms. These include environmental allergies, food allergies, anxiety, hives, motion sickness and more.

Because Benadryl can cause drowsiness, it is sometimes used for dogs with mild to moderate anxiety issues. Many dog parents give their dogs Benadryl during high-stress situations like thunderstorms or fireworks. Veterinarians will recommend its use in conjunction with heartworm treatment as it prevents allergic reactions associated with it. 

What Can Benadryl Treat In Dogs?

Benadryl is typically recommended by vets for dogs who are suffering from mild or moderate allergy symptoms. These allergies could be caused by seasonal allergies, environmental allergies such as grass, food allergies, or allergies that are caused by insect bites or snakes bikes. Similar to Claritin for dogs, Benadryl is commonly recommended for dogs who are sufferings from skin allergies and itchiness that is caused by this type of allergy reaction.

The most common symptoms that Benadryl can treat:

  • Itchy skin
  • Red or inflamed skin
  • Swelling and inflammation
  • Eye boogers or discharge buildup
  • Constant sneezing
  • Coughing or hacking
  • Runny nose or red eyes
  • Hives
  • Itchy or red ears

Recommended Benadryl Dosage for Dogs

Most drugstore diphenhydramine tablets, whether generic or brand name Benadryl, are 25 milligrams. As with any drug, the correct dosage of Benadryl for dogs depends on the dog’s weight.

Benadryl Dosage for Medium-to-Large Dogs

The standard dosage for a dog is 1 milligram per pound of body weight, so one tablet is perfect for a 25-pound dog. Veterinarians suggest giving a dose every 8-12 hours (about 2-3 times a day).

Benadryl Dosage for Small Dogs

Small dogs under 25 pounds can take the children’s formula of liquid Benadryl. Liquid children’s formula is easier for measuring the proper dosage for smaller dogs than the tablets. Stick to the children’s formula of liquid Benadryl as the adult version contains alcohol, which is toxic to dogs.

Benadryl Dosage Chart for Dogs

Benadryl Dosage for Dogs

Guidelines For Benadryl For Dogs

Never give a dog too much Benadryl — an overdose is possible. Abuse of the drug can result in fatal diphenhydramine poisoning, so always consult your veterinarian if you are unsure of proper dosage. Signs of overdose include constipation, agitation, dilated pupils, seizures, and rapid heart rate.

If your dog is suffering from an onset of a severe allergic reaction, use your best judgment to determine if it would be best to opt for an emergency trip to your veterinarian. There are cases where a veterinarian may need to inject an antihistamine under your dog’s skin in order for the medicine to act more quickly.

Also, avoid using time-release capsules for dogs. Time release capsules are absorbed differently in humans vs dogs, and may affect your dog’s dosage.

Benadryl Side Effects in Dogs

Just like any medication, Benadryl comes with potential side effects. Common side effects of Benadryl include drowsiness, dry mouth, urinary retention, hypersalivation, increased heart rate, and loss of appetite for some dogs. The side effects of Benadryl for dogs are typically thought to be minor as the medication is widely recommended for dogs. If you are worried about adverse reactions when you are trying to relieve symptoms, it is recommended that you monitor your dogs behavior when you give Benadryl to your dog for the first time.

You can find some peace in knowing that most veterinary practices will recommend Benadryl as a safe option for environmental allergens and other issues commonly found in dogs. In order to avoid some of these side effects it is important to remember to administer the proper Benadryl dosage for your dog as recommended by your veterinarian. 

How Long Does It Take For Benadryl To Work In Dogs?

Benadryl or Diphenhydramine is typically thought to be a fast acting medication for dogs. You can expect it to take effect in 1 to 2 hours but often times it will begin to work in under an hour. It is important to understand that it doesn’t begin working immediately and that it will take roughly an hour to reach its maximum efficacy. If you are planning on giving your dog Benadryl prior to playing outside in long grass, you should try to time it correctly so that the benefits align with your trip outside.

When to Avoid Giving Your Dog Benadryl

Benadryl may negatively interact with other medications. Do not use Benadryl with any central nervous system depressants, or on a pet with high blood pressure, seizures, bladder issues, lung disease, or glaucoma. If your dog is having difficulty breathing or swelling in the facial area, take them to the vet ASAP. It is always important to monitor how your dog reacts to medicine or supplements to make sure that your dog is reacting well to the ingredients. This is especially important if your dog has a known health history or if it is the first time you are giving this medication to your dog.

Can I Give My Dog Liquid Benadryl?

Benadryl comes in different forms that range from pills, liquid, or even Benadryl treats specifically designed for dogs. When you are giving your dog this type of medication it is important to first speak with your vet. Your veterinarian will have a better undestanding of the current health of your dog and any possible issues. Your vet will give you a recommended dosage of Benadryl based on the overall weight of your dog. This dosage will be in milligrams (mg). Once you know how many milligrams you can give to your dog, you must look at the label of your Benadryl to understand how much to give to your dog.

Liquid Benadryl or tablets will both list how many milligrams are within one serving. You should use this number as a reference in order to give your dog the correct and safe amount.

Is Benadryl Safe For Dogs To Calm Them Down?

Many dog owners will use Benadryl to calm their dog down as it can make them slightly tired, but this isn’t what the medicine is designed for. Benadryl and antihistamine medications are used to help alleviate allergy symptoms and as a side effect can cause your dog to calm down and become tired. Dogs that are incredibly active, anxious, or stressed out might not see much impact from this type of medication as it isn’t designed to calm dogs down, it is designed to help with allergies.

You can speak with your veterinarian on other alternatives for calming your dog down or dealing with anxiety or stress symptoms for your dog.

Alternatives Of Benadryl For Dogs

Benadryl is not the only solution for treating your beloved pet’s condition. If you would rather not use over-the-counter drugs for your dog, there are natural alternatives for controlling allergy symptoms and motion sickness.

Benadryl overdose is not common in humans or dogs but it is important for dog owners to understand that even FDA approved liquid Benadryl medication can be dangerous if you don’t give your dog the appropriate dosage. It is safe for dogs as it is just a mild sedative that is known for improving allergy symptoms or treat insect stings, but with any dog medication you must be careful.

Other over the counter medications don’t have the same active ingredient as a Benadryl tablet or an antihistamine drug. The following natural remedies are great options for providing the same kind of relief you can get from Benadryl.


When it comes to allergy symptoms like itchy red eyes, inflammation, sneezing, and runny noses in dogs, turn to nature’s Benadryl: quercetin.

Three strawberries on blue background

Quercetin is a flavonoid found in the peels of fruits and vegetables that contains anti-inflammatory, antioxidant, and anti-histamine properties. It is one of the most popular natural solutions that many dog owners and pet owners turn to when dealing with allergy symptoms. This is often recommended by dog owners who want to avoid the development of kidney disease in their elderly dogs. It is important to listen to veterinary advice on what is the best option for your dog.

To determine how much quercetin to give your dog, we’ll look at the recommended dosage for humans weighing 150 pounds: 1,000 milligrams. To convert this into the right dose for your dog, take your pet’s weight, multiply it by 1,000, then divide it by 150 to get the milligram dosage your pet needs. Viola! Quercetin occurs naturally in foods your dog can eat, too, like blueberries, strawberries, and spinach.

Fun fact for dog parents: Quercetin occurs naturally in red wine as well. Drink up and cheers to your health, bipeds!


CBD (cannabidol) is another natural alternative to Benadryl that is particularly great for dogs with adverse skin conditions. Yes, the word, “canna” is in “cannabidol,” but CBD has absolutely no THC (tetrahydrocannabinol) in it, or any psychoactive properties that get marijuana users high.

CBD for medicinal use is not derived from marijuana, but from agricultural hemp that possesses health benefits for humans and pets alike. Studies have shown that CBD can help relieve itchy and dry skin due to daily allergies or allergic reactions. It also works wonders for dogs that suffer from motion sickness and is worth giving a try before your next car ride with Fido. CBD comes in tablet form as well as oils, lotions, and balms that can be applied topically to the affected area.

All in all, CBD is a reliable natural solution for a variety of medical conditions in addition to symptoms of allergies. CBD is incredibly versatile and can also be used in dogs and people for medical conditions like anxiety, pain, nausea, and cancer.

Baking Soda

Need an easy and immediate solution for calming your dog’s red, itchy, and inflamed skin? Look no further than your kitchen. You can use it by making a paste or a spray solution. Make a paste by mixing baking soda with a little bit of water, then place it on the affected area for a few hours before washing off. To make a spray, use more water to baking soda, pour into a spray bottle, and shake before each use. If your dog is a licker, try covering the spot with a sock if it’s on their foot, or have them wear a cone while the paste treats the area. 

Dog Allergies: Causes and Treatment

Believe it or not, your dog’s allergy symptoms might be from the food they’re eating. The animal-based ingredients in dog food (beef, dairy, chicken, lamb, egg, pork, fish, and rabbit) are responsible for over 3 times as many food allergy cases as the plant-based ingredients. According to a study on, after five weeks of their dog patients “starting an elimination diet, more than 80% of patients had achieved a remission of clinical signs of CAFR [Cutaneous Adverse Food Reactions].”

That means your dog’s allergies could be eliminated just by changing what they eat. So before you give your dog any Benadryl, consider switching their dog food. 86% of customers reported a positive health benefit for their dog after switching to Wild Earth dog food!

We have a number of reviews from customers whose dogs no longer suffer from chronic itching, licking, inflammation, or gastrointestinal problems because of switching to Wild Earth dog food. Check out one of them in the video below!

Ease Your Pup’s Allergy Symptoms With Benadryl

Benadryl is safe for your pet and will help with their allergies or other symptoms. If you are considering Benadryl for your dog, it is vital that you make sure to give them the right dose.

If you are wary of giving your dog Benadryl, you have options. Natural alternatives to Benadryl for alleviating your dog’s allergy symptoms include quercetin, CBD, and baking soda.

If you are still unsure about which method is best for you and your pet, consult your veterinarian.