How much Benadryl can I give my dog? (A guide)


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Page last updated: 22/11/2022

How much Benadryl can I give my dog

In this guide, we will discuss “How much Benadryl can I give my dog?”, if Benadryl is safe to be administered to dogs. 

How much Benadryl can I give my dog?

You are thinking “How much Benadryl can I give my dog?” well we can tell you that according to PetMD the standard dosage for oral Benadryl is 1 mg per pound of body weight, administered 2-3 times a day, in addition, most drug store diphenhydramine tablets are 25 mg.

Which is the size used for a 25-pound dog. 

It is always important to check with your vet before you give any other Over-the-counter medication. 

Benadryl is used in humans as an over the counter medication to treat the symptoms of allergies, hay fever, and common cold all the time.

But how can you know it is safe for your dog or how much you should give to treat their allergy?

How much Benadryl can I give my dog? (A guide)

So what is Benadryl? Some may be wondering. Benadryl is the brand name for diphenhydramine, the active component or generic name.

It is considered one of the most sold over-the-counter medications when visiting a vet.

It is also considered safe and well-tolerated by pets but there are a few things that you as the owner should keep in mind before dosing it at home. 

There are many other brands with similar products, and other drugs under the Benadryl brand that you must be careful to avoid incorrectly using medication that contains other ingredients. 

If for instance, you don’t have Benadryl available to give your dog, you can should more about ‘What can I give my do for allergies?

 What is Benadryl normally used for?

Benadryl is an antihistamine and it basically works by blocking the H-1 receptors on smooth muscle and blood vessels.

Some of its most common indications are the treatment of environmental allergies, allergic reactions to insect bites or stings, and pre-treatment of vaccine reactions.

It also has some efficacy in the prevention of motion sickness in dogs and as a mild sedative (PetMD). 

It is believed Benadryl starts acting 30 mins after intake and it can be helpful if your dog has the following:

  • Irritated skin
  • Itchiness
  • Car sickness
  • Bee stings or insect bites
  • Asthma
  • Problems sleeping (insomnia)
  • Anxiety
  • Coughing or sneezing
  • Reactions to vaccination
How much Benadryl can I give my dog? (A guide)

When not to use Benadryl

  • If your pet has glaucoma, high blood pressure or any cardiovascular disease, then Benadryl is not recommended to be administered. The best thing to do is to get in touch with your vet for guidance before administering any medication. 
  • If you are giving your dog any other drug be careful because it might interact negatively with the components of Benadryl, first consult with your vet to make sure it is safe. 
  • If you suspect your dog is allergic or after administering a dose and results in an allergic reaction then stop Benadryl and go to see your Vet.
  • The most common side effect is sedation but if there are any additional side effects such as changes in their breathing pattern, heart rate, urination and in some rare occasions vomit and diarrhea. 
  • If you are not certain about the ingredients or what they could possibly do, do not administer Benadryl. Acetaminophen and Pseudoephedrine are not safe for dogs and they may come as ingredients in allergy medications. 
  • Overdose on Benadryl can become fatal. If you administered too much to your dog call the emergency vet or poison control hotline right away. Some of the symptoms include dilated pupils, constipation, faster heartbeat, behavioral changes, and even seizures. 
  • If your dog is pregnant or nursing it is not advised to administer Benadryl unless indicated by your vet and under their supervision.

How much Benadryl can I give my dog? (A guide)

How much Benadryl should I give my dog?

Even though we just answered this question previously, we can’t stress enough on the fact that it needs to be administered at the appropriate doses and following the instructions from your vet to avoid unnecessary medical complications.

As we discussed, the standard dosage for oral Benadryl is 1 mg per pound of body weight, given 2-3 times a day. 

According to One tablet on average can have 25 mg, so a 25-pound dog should be given one tablet.

Check the dosage on the package, and don’t assume that every product will be the same.

It is recommended to use the tablet form only since the liquid form may contain alcohol and it is toxic for dogs.

For smaller breeds, you can use the children’s formula since it is alcohol-free and it can become easier for you to measure and get the appropriate dose. 

There is also a topical form that can help when your dog has an itch. Fir any creams and gels it is necessary to follow your vet’s instructions.

Lastly, Benadryl can be given to your dog around every 8-12 hours, meaning 2 to 3 times a day but if you use it more frequently your dog can become tolerant of the drug and it will lose its effect. 

Recommendation from Pet MD: Always double-check the dosage before giving an over the counter medication.

In addition, many formulations are combined with other medications such as Tylenol so make sure Benadryl tablets contain only diphenhydramine.

When to contact your Vet

Oral Benadryl is considered to have a mild to moderately effective antihistamine property.

If your pet is having an allergic reaction with facial swelling or difficulty breathing, stop the medication and go straight to the vet. 

Some allergic diseases may require a combination of allergy medicine for dogs and treatment of other possible underlying infections.

If the medication is provided and your dog seems unresponsive to the treatment,  talk to your vet for other options. 

Additional recommendations 

Here are some additional recommendations in regards to your dog’s allergy management according to

  • Your dog may be allergic to many things, so depending on the reason for the allergy there are also different kinds of treatments available. 
  • If your dog is allergic to pollen, dust or any other allergens that he could bring home when he is playing outside. Make sure you are washing the bedding regularly to keep his bed clean from allergens. 
  • Occasional bathing is also recommended and frequent brushing to help keep the allergens away. 
  • Some allergies are caused by food. These are very difficult to determine or spot but if you suspect it can be a food allergy talk to your vet. They can actually make some recommendations and dietary changes to help alleviate the symptoms. 
  • If your dog is constantly suffering from seasonal allergies, there are also other natural remedies you might want to consider. For instance, Apple cider vinegar, coconut oil or aloe vera are excellent choices when treating an uncomfortable itch. 
How much Benadryl can I give my dog? (A guide)

Natural remedies: alternative options 

Here are five natural remedies to help fight seasonal allergies symptoms (


This is a flavonoid that gives plants and vegetables their pigments. It has antioxidant, antihistamine and anti-inflammatory properties.

It helps reducing itching and fighting cellular activity that is responsible for inflammation.

Additionally, it can be used for treating asthma and respiratory issues since it reduces inflammation. 

Bromelain and Papain

They are proteolytic enzymes that are responsible for breaking down proteins. Bromelain comes from pineapples and papain from papayas.

They help increase the absorption of quercetin and also help reducing pain and inflammatory in mucous membranes and in various other parts of the body

Oath baths

If your dog has a yeast infection or you are not sure, avoid using oat. Oat is considered a source of carbohydrates, which will only make yeast grow even more. 

But if the itching is due to allergies then, an oath bath can be very soothing. Just simply boil oat straw in the water and mix it when bathing your dog. 

Aloe Vera

Aloe vera is wonderful for many reasons and it is frequently used due to its antibacterial and antioxidant properties. 

When using the aloe vera for your pet, make sure you don’t use the whole leaf since it contains saponins which are a laxative and can make your dog very sick. Try only using the gel. 

If you are not sure how to do it directly from the aloe vera leaf then you can also buy the cream at a homeopathic store or drug store. 

How much Benadryl can I give my dog? (A guide)


As Quercetin, thyme contains flavonoids. Besides the antioxidant and anti-inflammatory properties, it also has antibacterial and antifungal properties, which makes it very good to treat yeast infections. 

If your dog is chewing its paws very frequently try making an infusion out of thyme and apply to the area. 

Why is this blog about “How much Benadryl can I give my dog?” important?

It is important to be aware not every over the counter medication that seems effective in humans to have the same effect in dogs.

Their bodies react differently to some medications that are considered safe for humans and can escalate and become a life-threatening situation very fast. 

We know your dog’s safety comes first and it is a priority, so be careful and always read the components from the medication, if you are not sure do not administer it and ask your vet for advice. 

If you have used Benadryl or you are going to start using it, please let us know any comments about it in the comment section down below!

Frequently Asked Questions (FAQ’s) about How much Benadryl can I give my dog?

Can you overdose your dog on Benadryl?

Yes, and an overdose on Benadryl can become fatal.

If you suspect your dog ingested too much, contact emergency vet or poison control hotline. 

What does Benadryl do for a dog?

Benadryl, when administered to dogs, can treat mild to moderate allergies.

It is also used to treat itchiness caused by some skin allergies. In general, Benadryl reduces allergic symptomatology. 

How much Claritin can I give my dog?

The recommended Claritin dosage is 0.2 mg of Claritin per pound of weight.

Every dog is different so follow the prescription instructions from your vet.

Can you give a dog Claritin instead of Benadryl?

It is not safe to give your dog Claritin if it comes with pseudoephedrine. This can become fatal.

If Claritin comes only with the main component loratadine then it is safe for dog intake, but follow the instructions from your vet and always read the ingredients before administering. 

Which antihistamine is best for dog allergy?

The best antihistamines for dog allergies are Benadryl (diphenhydramine), Zyrtec (cetirizine) and Claritin (loratadine).

They all relieve allergy symptoms or help to counteract allergic reactions.

One of the side effects is drowsiness for some dogs and for others, they can become hyperactive.  

  1. Dog Allergies 101: How to Stop the Itching, Scratching, and Painful Vet Bills


Pet MD


Natural remedies for dogs with seasonal allergies