Your Pet, Our Passion.
can dogs have benadryl

Can You Give Dogs Benadryl?

2 min read

From digestive problems in dogs to coughing, our pets can sometimes be subjected to health issues that need treatment – especially our pooches that are prone to getting into trouble when they explore outside. From being stung by bees, to being a little too curious with stinging nettles, they can give themselves allergic reactions. As Benadryl helps us humans with our allergies so well, you might be wondering ‘can I give Benadryl to my dog?’ Find out if you can and if so, how much is safe for them to take. 

What is Benadryl?  

Diphenhydramine, more commonly known to us as Benadryl, is an antihistamine which relieves the symptoms of allergies. For us humans, it’s a great antihistamine and for our dogs, it can be great too (in the correct dosage). Vets use Diphenhydramine to treat allergies and allergic reactions to insect bites/stings. It works by blocking the H-1 receptors on smooth muscle and blood vessels. 

What does Benadryl treat in dogs?  

Benadryl for dogs can be good for treating mild dog allergies and things like motion sickness when travelling with your dog. It’s important to make sure this is given with your vet’s advice and in the correct dosage (more on this later on).  

Benadryl for dog allergies 

For dogs who have might have gotten a little too nosey, Benadryl can be used as an antihistamine. If they’ve been bitten or stung by an insect, it can be moderately effective for mild allergic reactions in dogs.  

In some cases, Benadryl for dogs can be used for pre-treatment when your dog is given a vaccine. Though, this should be checked with your vest first. 

Benadryl for dog travel and anxiety 

When travelling with your pooch, it’s possible that they will get motion sick. For long distances, the right dosage of Benadryl can help with this and can be safe.  

Some pooches get scared during thunderstorms or when fireworks are out to play. Benadryl (in the correct dosage) can act as a mild sedative. Though, this does depend on your dog as some can actually have the opposite reaction. 

How can I tell if my dog is having an allergic reaction? 

As we mentioned, Benadryl for dogs can be beneficial for your pooch. But what are the signs your dog may need Benadryl if they’re experiencing allergies? Here are some common symptoms: 

  • Itchy skin 

  • Recurring ear infections 

  • (Clear) runny nose  

  • Red and swollen eyes 

  • Sneezing fits 

Can I give Benadryl to my dog?  

As we suggested previously, you can give your dog Benadryl. Now you might be wondering ‘how much Benadryl can I give to my dog?’ Well, the amount depends on the size and weight of your dog. Each dog is unique and can react differently. We always suggest to ask your vet before you administer any Benadryl treatment. 

It’s highly important to get the dosage correct as most Benadryl tablets are meant for human consumption. Because of their size, the dosage of Benadryl for dogs might be less than humans. Our pooches metabolise it differently, so it’s imperative to work out the right dosage. 

It’s important to note: Benadryl should not be given to dogs with some health conditions. Similarly, Benadryl can also react with some other medications that your dog might be taking. For both these reasons, it’s again imperative to consult your vet first. 

Benadryl Dosage for Dogs

As we said, the correct dosage depends on your dog’s weight. The Merck Veterinary Manual suggests that the safe dosage is 2-4 milligrams of medication per kilogram of weight. This amount can be administered two to three times daily, depending on your dog’s symptoms.  

Some things to note about Benadryl for dogs: 

  • Smaller dogs might do better with children’s Benadryl (consult your vet first) 

  • The Benadryl must be only diphenhydramine – no other active ingredients 

  • Never give your dog time-related capsules – there’s a risk of overdose 

  • Ask your vet before giving the liquid version of Benadryl – these work slightly differently

Side effects of Benadryl in Dogs 

Though we’ve answered the questions ‘can I give my dogs Benadryl?’ and ‘how much Benadryl can I give my dog?’, it’s important to keep in mind that there can be (not so dangerous) side effects. 

  • Increased heart rate 

  • Sleepiness 

  • A dry mouth 

  • Fast breathing 

  • Hypersalivation  

If your pooch experiences any of these, it might be a good idea to call your vet. 

Allergy to Benadryl for Dogs 

More severely, your dog might have an allergy to diphenhydramine. Of course, we suggest consulting your vet but here are some symptoms to look out for:  

  • Swelling of face and tongue 

  • Vomiting, diarrhoea and an upset stomach 

  • Licking or chewing their skin 

  • Red rashes on skin 

When to contact your vet 

In an emergency, you should always call your vet immediately. Your dog might be experiencing anaphylactic shock, either from allergies or (as we mentioned) from Benadryl itself. Call your vet if your dog is: 

  • Vomiting 

  • Experiencing diarrhoea  

  • Swelling 

  • Struggling to breathe 

  • Experiencing seizures 

Your dog may need immediate treatment. If you’re not sure what your dog has been bitten or stung by, it may be serious. To ensure your dog isn’t poisoned, call your vet immediately. The sooner you get help, the better! 


If you’re wondering if you can give your dogs Benadryl, you might be wondering ‘Can I give my dog Ibuprofen?’