Can I Give My Boxer Benadryl? Cautions And Alternatives

Owners frequently suggest Benadryl to each other for their Boxers, and many vets are willing to recommend this over-the-counter drug for allergy-like symptoms.

Despite its availability and popularity, Benadryl is not a medication you should give to your Boxer lightly — or in lieu of addressing the underlying cause of the hives or the itching.

I am not a vet. This post is intended for general educational and informational purposes. I encourage readers to view my full disclaimer.

What Is Benadryl For Boxer Dogs?

Benadryl is the brand name of the drug diphenhydramine hydrochloride, invented by the company that’s now part of Pfizer, and approved as the first prescription antihistamine in the 1940s.

Antihistamines counteract histamines, natural body chemicals involved in many processes including the dilation of blood vessels as part of an immune response to pathogens.

An over-release of histamine is associated with allergic reactions that may damage capillaries and allow blood plasma to leak into tissues, creating inflammation and itch.

Benadryl was designed for use in people but is now frequently given to dogs.

You may have encountered it as Vetadryl, a liver flavored version for pets.

As well as being an antihistamine, Benadryl has other effects including sedation.

It is given to dogs for just about anything from allergies and anxiety to motion sickness and as an antidote to adverse vaccine reactions.

Can You Give A Boxer Dog Benadryl?

Ask your conventionally-trained vet whether you can give Benadryl to your Boxer and the answer is bound to be yes.

Benadryl is often the gateway drug to a slew of “allergy” meds encompassing immunosuppressant steroid injections or prednisone tablets, regular Cytopoint shots and ofen culminating in Apoquel, a drug that comes with an increased risk of tumors and which many owners find involves a nasty detox if you ever try to discontinue it.

Note that none of these “treatments” address — or even try to identify — the underlying cause of the dog’s symptoms.

They suppress or mask symptoms, in some cases.

When you give these drugs you may achieve temporary relief, but you are no further advanced in solving the root cause of your dog’s problem.

So, while you can give your Boxer Benadryl, whether it’s a good idea is a different question.

Is Benadryl Safe For Boxer Dogs?

The standard advice is that Benadryl is considered safe when dosed according to the veterinary recommendations (see dosage recommendations lower in this article).

However, if you are looking for a safer, lasting solution to your Boxer’s allergies or other symptoms, you may wish to look deeper than the quick fix that is Benadryl.

What Can I Give My Boxer For Allergies Instead Of Benadryl?

Rather than medicate your Boxer in a bid to cover up symptoms, it’s best to identify the cause of those symptoms.

Likely culprits, often in combination, are:

Natural Alternatives To Benadryl For Boxers

As well as identifying and removing the cause of your Boxer’s symptoms, there are a number of things you can do instead of giving your Boxer a drug like Benadryl.

Safer options that can benefit your Boxer include:

  • Feeding a fresh, natural raw canine diet
  • Fasting — resets the immune system and accelerates the body’s natural detoxification pathways in the liver
  • Including quercetin-rich foods in his diet — quercetin is plant compound known as Nature’s Benadryl because of its anti-inflammatory properties. While it can be bought as a supplement, it’s also available in whole food form in berries and apples (leave the skin on) which are one of the many types of fruit your Boxer can eat
  • Using homeopathic remedies instead of pharmaceuticals for insect stings — options include Ledum palustre 30C or 200C (the first choice for cold and puffy bites) and Apis mellifica 30C or 200C (try first for very swollen and red stings with itching and possibly pain)
  • Giving CBD oil can be helpful for anxiety — make sure it’s properly sourced from a quality supplier
  • Practice and time can be all that’s required to outgrow motion sickness — here are some ideas for teaching your Boxer to ride in the car
  • Bathing less often — if you’re washing your Boxer more than four times a year, it may be the cause of his skin problems. There are many causes of itching and histamine release is only one pathway. Frequent washing strips essential oils from the coat, making the skin prone to tiny cracks called microfissures which, in turn, cause itching

Regardless of your Boxer’s issue, fix the basics first and see if you actually have a problem.

There is every chance the symptoms that are being attributed to “allergies” may actually be a normal reaction to poor diet or other mistakes in basic dog husbandry.

These mistakes are all too easy to make, as so many of the practices that are normalized as part of modern dog ownership run counter to your Boxer’s health.

What Benadryl Is Safe for Dogs?

If you are going to give Benadryl to your Boxer, it’s best to use a formula that’s specifically intended for dogs.

Many owners use a human product bought at the pharmacy.

If you’re doing this, it’s imperative that you check the label and make sure you get a product that contains only diphenhydramine and no other active ingredients.

Some cautions if using Benadryl with your Boxer include:

  • Never give your Boxer Benadryl that is combined with decongestants or alcohol, which can be toxic to dogs
  • Never use time-release drug capsules which run the risk of overdosing your dog because of the way the canine stomach works and because your Boxer may bite the capsule as he swallows it, releasing the entire dose at once
  • Use Benadryl tablets, not liquid made for children which is sometimes recommended because it’s alcohol-free but which is absorbed differently, may require a different dosage and contains chemicals and dyes that can harm your Boxer
  • Avoid Benadryl with dyes
  • Always read the ingredients and make sure there is no xylitol in the formula (this sugar alternative is deadly to dogs)
  • Never give Benadryl to a Boxer puppy, a pregnant Boxer or a Boxer with pre-existing health conditions like heart disease
  • Because of potential drug interactions, don’t give Benadryl to your Boxer if he’s on other medications such as sedatives or pain meds — check with your vet

What Does Benadryl Treat In Boxer Dogs?

For better or worse, owners most commonly give their Boxers Benadryl for:

  • Itching
  • Anxiety including separation anxiety
  • Allergies including seasonal allergies and food allergies
  • Hives — note that Benadryl may not get rid of the hives any quicker than they’d normally disappear on their own, but can make your Boxer more comfortable in the meantime
  • Bee stings
  • Motion sickness
  • Thunderstorm phobia or fear of fireworks
  • Skin rashes
  • Vaccine reactions (Some vets dose with Benadryl prior to vaccinating dogs that have previously had adverse reactions, though such dogs should not receive any more vaccines)
  • Mast cell tumors (Because they can cause histamine release)
  • Reverse sneezing

Side Effects Of Benadryl For Boxer Dogs

Like any drug, Benadryl comes with a range of side effects, some mild and others severe.

Common, mild side effects of Benadryl in Boxer dogs include:

  • Drowsiness (although excitement can also occur)
  • Dry mouth, nose and throat
  • Rapid breathing
  • Hypersalivation or drooling
  • Rapid heart rate

But Benadryl’s side effects in dogs can be even more serious.

Antihistamines cross the blood brain barrier and, as a result, can cause significant suppression of the central nervous system and toxicity, which can result in impaired movement, coma and even death.

Other possible adverse effects of Benadryl on your Boxer include:

  • Low blood pressure
  • Heart palpitations
  • Cognitive issues including confusion, dementia
  • Anxiety
  • Mood disturbances and depression
  • Trembling
  • Nausea and vomiting
  • Change in appetite
  • Constipation
  • Masked symptoms of gastrointestinal problems.

Note that Boxers are a breed that tends to have a sensitivity to drugs e.g. the common veterinary sedative Acepromazine which is one reason they benefit so much from natural rearing practices.

It’s important to observe your Boxer closely if you do give him Benadryl, to make sure he doesn’t suffer an allergic reaction to the drug itself.

It can become complicated, as signs your Boxer is allergic to Benadryl include many of the symptoms for which you may have given the Benadryl in the first place such as:

  • Red skin rash
  • Swelling of face and tongue
  • Skin chewing or licking
  • Stomach upset including diarrhea and vomiting
  • Breathing difficulties

These reactions will ordinarily show themselves within an hour of receiving the drug.

Benadryl Dosage For A Boxer Dog

Dogs metabolize Benadryl differently to people, so if you’ve bought medication intended for humans, the dosage guidelines on the packet don’t apply.

According to the Merck Veterinary Manual, the canine dosage of Benadryl is about 1mg per pound (2-4mg per kilogram).

Never try to guess how much to give.

This is one situation where you need to ask your vet.

If Benadryl is working for your Boxer, it’s said to begin reducing symptoms of something like skin rashes within about an hour.

If your Boxer is having an adverse reaction to the Benadryl, its effects should wear off after 24 hours.

Beware that Benadryl has a narrow safety margin, which means it’s easy to give too much.

Signs of Benadryl overdose include:

  • Red eyes
  • Dilated pupils
  • Intense drowsiness
  • Rapid heart rate
  • Breathing difficulties
  • Aggression
  • Fever
  • Seiures
  • Muscle tremors
  • Lack of coordination, inability to walk
  • Difficulty urinating
  • Delirium

These symptoms can progress to:

  • Anaphylactic shock
  • Seizures
  • Respiratory failure
  • Coma

Contact your vet immediately for emergency treatment if you suspect Benadryl overdose.

How Often Can I Give My Boxer Dog Benadryl?

The Merck Manual says the above dosage of Benadryl can be administered two to three times per day i.e. every eight to 12 hours.

Benadryl should only ever be used for the shortest possible duration.

If your vet suggests keeping your Boxer on Benadryl long term, run a mile.

Many of the worst adverse consequences of Benadryl arise from extended use.

Hopefully you can find a good holistic vet who has a more extensive array of tools in her kit bag and is less likely to automatically reach for drugs as a first resort.

If there are no holistic vets in your area, some offer telehealth consults long distance.

Other Drugs Sometimes Given Instead Of Benadryl

Other drugs sometimes given in place of Benadryl include:

  • Zyrtec (cetirizine)
  • Claritin (Ioratadine)

Beware that these drugs are often combined with decongestants that are dangerous for dogs.

When Benadryl May Not Be Enough

For acute allergic reactions involving swelling that may threaten the airway, faster acting drugs that begin to work within minutes, like a steroid shot, may be necessary.

Steroids are best reserved for emergencies and used for the shortest possible duration, given the damaging effects these immunosuppressant drugs can have on your Boxer’s overall health.

Similarly, snake bite usually requires immediate treatment with a specific drug called antivenom.

Here again, consult your vet for advice.


Before you reach for Benadryl to deal with your Boxer’s symptoms, try getting to the bottom of what’s causing the problem.

Far better to identify and remove the root cause than to medicate your dog while the underlying issue persists.

The kinds of symptoms typically suppressed with Benadryl can usually be resolved once and for all with proper diet and care.


Fein, MIchael N et al, CSACI position statement: Newer generation H1-antihistamines are safer than first-generation H1-antihistamines and should be the first-line antihistamines for the treatment of allergic rhinitis and urticaria, Allergy, Asthma and Clinical Immunology, 2019

Henriques, Julia, Benadryl: Not As Safe For Dogs As You Think, Dogs Naturally Magazine, 2021

Merck & Co., Inc, The Merck Veterinary Manual, 11th Edition, Whitehouse Station, 2016