Can I Give my Dog Benadry and How Much?

However tempting it is to try to help your pup by giving it your own medicine, this could be a dangerous practice. Always use human medications only after asking your vet, or if you are sure that the dosage and the drug are safe for your pup.

Benadryl is a human medication that veterinarians commonly prescribe for pups as well.

It is an antihistamine that can help your dog with certain types of allergies or other conditions.

It is considered safe to use with canines, but it is vital that you give the pup the right dosage and be aware of the potential side effects it can have.

Here is everything you need to know about using Benadryl for dogs, including the content, the usage, the dosage, the side effects, and the diagnosis and treatment of Benadryl overdose in pups.

You can also find out more about some home remedies which you can use instead of Benadryl if you prefer more natural and safer solutions to your pup’s health issues.

What exactly is Benadryl?

Benadryl is the brand name of the over-the-counter antihistamine which can help relieve hay fever or other allergies and can also be used for treating the common cold, hives, insect bite itching and other conditions in humans.

Its generic name and the main active ingredient is diphenhydramine HCL.

Benadryl is sold in various forms in pharmacies, including tablets, capsules, chewable tablets, oral liquid solution, and topical spray, cream, gel or stick.

It is also available in other generic forms.

It is still not approved by the FDA for veterinary use, but most veterinarians consider it safe for cats and dogs.

It is mostly used to treat certain dog allergies such as pollen or other environmental allergies as well as flea bite allergies, but also for motion sickness as well as a mild sedative.

It is always important that you speak to your vet before consider giving your dog Benadryl.

How exactly does Benadryl work?

Diphenhydramine is a first-generation antihistamine that can cross the blood-brain barrier and acts as a receptor antagonist, and it blocks the receptors in the body which receive histamines. This can help relieve a lot of the symptoms associated with seasonal and other allergies, including itchy skin, hives, sneezing, and others.

While the body continues to produce histamines, the H-1 receptors of the smooth muscles and blood vessels are blocked from registering them. As a result, any unpleasant allergic reactions are reduced.

Benadryl also works as a mild sedative on canines and can sometimes be used to treat anxiety or other conditions in pups.

Apart from being highly effective for alleviating allergy symptoms, because of the ability of the active ingredient of Benadryl to cross the blood-brain barrier, there are some adverse reactions that can occur in dogs as well.

How can Benadryl help dogs?

Treating allergies

Benadryl is pretty efficient for treating mild or moderate allergies in dogs. Some of the common allergies which respond well to treatment with this antihistamine include:

  • Seasonal allergies
  • Food allergies
  • Flea bite allergies
  • Snakebite allergies

And here are the symptoms caused by allergies that Benadryl can help alleviate in pups:

  • Itching
  • Swelling and inflammation
  • Hives
  • Runny nose and eyes
  • Redness
  • Sneezing
  • Coughing
  • Anaphylactic shock

Please note that any of these symptoms can be caused by something else, so make sure the dog has been diagnosed with an allergy before proceeding to treat it with Benadryl or with anything else for it!

Also, it is essential to understand that Benadryl will not cure the allergy – but it will simply alleviate the unpleasant allergic reactions and make life easier on you and on Fido.

Helping pups with anxiety or motion sickness

Since one of the side effects of Benadryl is drowsiness, it is sometimes used to calm down anxious dogs, especially dogs which suffer from mild to moderate anxiety and motion sickness during travel.

It has been found that Benadryl can help calm down the dog when it travels by car or plane.

The drug can also help relieve the anxiety in some dogs caused by other factors.

For dogs with mast cell tumors

These are tumors on the connective tissues such as the skin, mouth, nose, and lungs. The mast cells serve as a protective barrier against parasitic infections as well as for tissue repair and for forming new blood vessels.

Mast cell tumors are especially common among Boxers, Boston Terriers, Pugs, and Bulldogs.

Benadryl has been found to help alleviate the effects which the histamines released by the affected cells cause.

Preventing allergic reactions during heartworm treatment

Benadryl is also used by vets to help avoid allergic reactions in dogs during heartworm treatment and has been found to be very effective in reducing these adverse reactions while the dog is being treated.

What is the proper dosage of Benadryl for dogs?

The safe and effective dosage depends on the size, weight, and condition of your dog.

Always ask the vet about the proper dosage to give to your fur baby.

Typically, Benadryl is used in tablet form when treating dogs.

The rule of the thumb is to give 1mg of Benadryl per 1 lb. of the bodyweight of the dog. The medication is usually taken 2 or 3 times a day at least 8 hours apart.

Do not give your dog time-release capsules, because these are absorbed very differently by canines than by humans. Such capsules can get broken if chewed and as a result, release too much of the active ingredient at once.

This can cause an overdose and even poisoning of the dog.

The dosage for the different forms of Benadryl is different, so make sure you speak to your veterinarian about the safe dosage for the type you are planning to use for your dog.

If you decide to use oral liquid Benadryl, make sure you opt for the kid formula, as it doesn’t contain alcohol which can be toxic for dogs. Use a syringe to make sure the dosage is correct, and also to make giving it to the pup easier.

Pick the children’s pills when you are giving Benadryl to a very small dog too.

The medication usually takes about 30 minutes to start working, so make sure you plan accordingly if you are going to give it to your pup for motion sickness, for anxiety due to a particular event, or as a precaution before going out during hay fever season.

Some dogs which suffer from chronic allergies may need to take Benadryl on a daily basis. If this is the case, you should still regularly consult with your veterinarian, as the doses may need to be corrected over time if the dog gains weight, or as it grows older.

Also, the medication can begin losing its effectiveness after prolonged administration which is something to keep in mind as well.

Most importantly, just like with humans, all dogs are different and can respond differently to Benadryl as well as to any other medication.

Therefore you need to discuss what the best option is for your dog with the vet and monitor it closely for any side effects or signs of overdose or poisoning when you start giving it Benadryl or any other drug.

If you are going to use a topical form of Benadryl on your dog, also make sure to speak to the veterinarian first about the quantity and the way to apply it, as well as how often you should reapply the cream, gel or another liquid topical form of the medication.

If you choose another generic form of the active ingredient, make sure it doesn’t contain ingredients like Pseudoephedrine or Acetaminophen which can be toxic to dogs.

Make sure the medication is not combined with others like Tylenol, and that they contain only the active ingredient – diphenhydramine.

What are the possible side effects of Benadryl in dogs?

All dog parents should be aware of the possible adverse effects of Benadryl, as well as any other medication they give to their pups.

It is essential to watch for any side effects, especially the more serious ones, especially when you first start giving your dog Benadryl, because they may interact with other medications or worsen another underlying health issue.

Some of the more common side effects of Benadryl on dogs include:

  • Drowsiness and sedation
  • Urinary retention
  • Dry mouth
  • Increased heart rate
  • Hypersalivation
  • Rapid breathing

Here are some of the possible rarer side effects of Benadryl on dogs:

  • Vomiting
  • Diarrhea
  • Increased appetite
  • Decreased appetite

Since most of the adverse effects are likely to occur within an hour after the dog has taken the medication, you should watch it closely during that time.

When should Benadryl be avoided?

If your pup has another underlying health condition such as high blood pressure, glaucoma or cardiovascular disease, if it is pregnant, or has other preexisting health problems, you should consult with your veterinarian about giving it Benadryl.

Here are some common health issues which could be worsened by taking Benadryl:

  • Angle-closure glaucoma
  • High blood pressure
  • Severe heart failure
  • Allergic lung disease
  • Prostatic hypertrophy
  • Seizure disorders
  • Bladder neck obstruction
  • Pregnancy or nursing

Your dog may also have an allergic reaction to Benadryl no matter how ironic it may sound to have an allergic reaction to a medication for allergy relief.

If you suspect that your dog has had an overdose of Benadryl, you should contact your veterinarian immediately or call the poison control hotline.

Some of the symptoms that your dog has had too much Benadryl are dilated pupils, rapid heartbeat, seizures, constipation, or changes in behavior.

Read on to find out more about Benadryl overdose in dogs, and what to do if it happens with your pup.

Also, do not attempt to treat an acute allergic reaction of your dog with Benadryl or other home remedies. If the dog is showing signs of severe allergy such as facial swelling and difficulty breathing, you should rush it to the veterinary clinic immediately!

Benadryl overdose

It is possible for your dog to overdose on Benadryl, and such an overdose can be fatal if not treated immediately.

Usually, an overdose or poisoning with Benadryl is not caused by you giving the dog too much medication, but rather because it has gotten to the medication and has ingested too much of it on its own.

The first symptoms to look for if you suspect that your dog has overdosed on Benadryl are:

  • A rapid heartbeat
  • Agitation
  • Aggression
  • Dilated pupils
  • Difficulty breathing
  • Erratic behavior
  • Constipation
  • Seizures
  • Extreme drowsiness
  • Fever
  • Muscle tremors
  • Red eyes

If you see any of these symptoms or you think that your pup may have overdosed on Benadryl, call the emergency veterinary hospital or the pet poison hotline immediately.
Also, if your dog is showing signs of experiencing an allergic reaction to the medication, you should contact the veterinary office immediately.

Always monitor the dog carefully when you administer Benadryl for the first time!

Treatment of Benadryl Poisoning in Dogs

If you have actually seen your dog ingesting dangerous amounts of Benadryl, or it looks like it has had an overdose, then you should rush over to the veterinary emergency clinic immediately.

If possible, you should bring the package which the dog has found with you. It will give the vets an idea of the type of medication as well as the quantities, and other ingredients ingested which could be causing the poisoning.

Be ready to provide the vets with all the information you have about the type of Benadryl, the possible quantities the dog has ingested and other questions relative for the current emergency and the overall health of your pup.

The veterinarians will measure and weigh the pup, and a complete blood count, analysis of the urine, and a biochemistry profile will be performed right away.

Unfortunately, there are no tests that can detect Benadryl in the dog’s urine, so the diagnosis of Benadryl overdose or poisoning is done mainly based on the symptoms and the timing.

In case, you see your dog ingesting big quantities of Benadryl but do not see any obvious symptoms of an overdose or poisoning, you should still go to the veterinarian immediately. It is very likely that they will be able to induce vomiting in the dog so that it can get rid of all or most of the ingested tablets before they can harm its nervous system, the cardiovascular system, and the rest of its body.

In milder cases when the dog has swallowed smaller quantities of Benadryl less than an hour ago, your vet may suggest that you try to induce the vomiting yourself by giving a simple hydrogen peroxide solution of a teaspoon per 5 pounds of the body weight of the dog.

Before attempting to deal with the crisis on your own, call the vet to check if it is alright to do this at home.

Never attempt to induce vomiting in a pup who is unconscious, has problems breathing, or is in a shock or serious distress!

Go to the emergency veterinary hospital immediately instead.

To treat Benadryl overdose, the vets will usually use activated charcoal which will soak up as much of the toxin as possible from the stomach of the dog.

Also, in some cases, gastric lavage may be performed to empty the pup’s stomach completely.

Most likely, your dog will receive IV fluids and electrolytes to help prevent dehydration, and electrolyte imbalances as well as to make the administration of medications for the other symptoms easier.

The temperature of the dog will also be monitored closely to watch for bouts of fever which too must be addressed immediately.

The cardiovascular system will also be monitored by the vets because overdose with antihistamines can often lead to high blood pressure, and increased heart rate, and other cardiovascular problems too.

When emergency actions are taken as soon as possible, and the vets manage to get most of the ingested pills out of the stomach of the poisoned dog, and proper care is taken to keep it hydrated and treated for the other effects of the overdose, the recovery should be complete.

Unfortunately, in some cases, Benadryl overdose can be deadly as well.

This is why you should never keep your pills lying around the house, or sitting on low furniture.

Puppy-proof your home, and keep all medications and other potentially toxic substances away from your curious pup!

Also, follow the strict guidelines given by the veterinarians when giving your dog any kind of medication!

So, is Benadryl actually safe for dogs?

Although it has not yet been FDA approved for use in dogs, Benadryl is relatively safe and can be quite effective when administered in accordance with the instructions of the veterinarian.

Just like with any other new medication, monitor your dog carefully after you give it Benadryl for the first time. Watch for any signs of an allergic reaction to the drug, or for other side effects, so that you can take action immediately if necessary.

Is it safe for a dog with environmental allergies?

Dogs often suffer from environmental allergies which can be caused by various airborne allergens such as pollen, mold, dust, chemical fumes, cigarette smoke, and other substances which the dog inhales.

The allergic reactions to them are usually extreme itching due to allergic atopic dermatitis. The dog will start scratching its head and then intensively scratching its entire body.

Although Benadryl can be quite effective for alleviating allergic reactions to environmental allergens, there are other medicaments such as cortisone which are much more effective for canines.

Is it safe for dogs with flea allergies?

If your dog has flea allergy or is showing signs of allergy as a result of another insect bite, such as inflammation and swelling of the skin and warmer temperature in the area of the sting, then it is safe to administer Benadryl to help relieve the symptoms. Give the pup about 1mg per pound of its weight.

Is it safe for severe allergic reactions?

No, if your dog is showing signs of an acute allergic reaction which includes symptoms like difficulty breathing, swelling of the face, or others, you should take it to the vet immediately. A severe allergic reaction can lead to anaphylactic shock and even death if not treated in a timely manner.

So, forget about human medications and the other home remedies in this case. This should be considered a medical emergency.

Is it safe for pups with anxiety?

Many dogs suffer from anxiety. Some are anxious when left alone, others hate traveling, some are scared to death during thunderstorms or fireworks and some can get anxious about just about anything.

Although Benadryl is sometimes prescribed as a mild sedative to relieve anxiety in dogs, there is no one clear-cut answer to whether it is safe to give Benadryl to all dogs with anxieties.

The drowsiness this drug causes is not the purpose of this medication but rather a side effect, so you should be careful and always talk to your vet if you are considering using Benadryl as a mild sedative on your dog.

In case, you have already tried it, and it has had a positive effect on your dog, you can give it to the pup about 30 minutes before the expected events which cause the anxiety. It takes about half an hour for the medicine to kick in, so plan ahead if you want it to be efficient and your pup to be calmer when the time of the anticipated anxiety comes.

Is it safe for dogs with motion sickness?

The antihistamine acts as a mild sedative in some dogs and can help make short trips or infrequent travel much less stressful for the pup.

Speak to your vet about the proper medication to use if you are going on a longer trip, or if your dog is experiencing severe motion sickness including extreme agitation, barking, vomiting, and defecation while you are on the road or on a plane.

Your veterinarian may suggest you try other ways to reduce the stress from traveling such as playing music, keeping the dog away from the window, wearing thunderhsirts or others.

Keep in mind that the sedentary effect of Benadryl can continue lingering on even after the trip is over, and can cause grogginess and disorientation in your fur baby.

So, you should use Benadryl for dogs with motion sickness as rarely as possible, and in accordance with the instructions given by your vet for the dosage and time of administration for the best effect with minimum side effects.

Is Benadryl safe for dogs that are hyperactive?

It does act as a sedative and can make a hyperactive dog drowsy and sleepy, but you shouldn’t use Benadryl as a dog tranquilizer on a regular basis.

Instead, try to keep the dog active during the day and provide it with enough exercise so that it can rest and sleep calmly after that.

Dog medicaments which are alternatives to Benadryl

If you are not happy with the effect which Benadryl has on your dog for treating its allergy, you may want to ask your veterinarian for other suitable medications to alleviate the symptoms or for ongoing prevention of allergic reactions.

Some of the most common medicaments used to treat canine allergies, anxiety, and motion sickness which are excellent alternatives to Benadryl include:

Vetadryl – this is a veterinary product that is another version of diphenhydramine just like Benadryl, but it is specifically formulated for use in dogs and cats.

Chlorpheniramine – this is an antihistamine that is often used for dogs and is less likely to cause drowsiness as a side effect.

Clemastine – this is an antipruritic and sedating antihistamine which has fewer negative side effects than others.

Hydroxine – this is a more aggressive antihistamine, which though has more potential adverse effects.

Meclizine – is a medicament used to resolve nausea including vomiting caused by motion sickness.

Home remedies that can replace the use of Benadryl

If you are not comfortable giving your dog human medication such as Benadryl but want to help alleviate its allergic reactions to different environmental factors, foods, flea bites, or contact with allergens, there are quite a few, highly efficient and completely safe home remedies you can try instead.

Read on to find out how to help your dog cope with its allergy without medications:


Quercetin is a flavonoid that gives fruits and veggies all those beautiful colors. It is a compound in plants that has antioxidant, anti-inflammatory, and antihistamine properties as well.

It can efficiently help reduce itching by fighting inflammation.

It is also used to treat asthma, respiratory problems, and cancer prevention.

Quercetin is available in capsule or pill form and should be given in the right dosage for the best effect. Multiply the weight of your pup and multiply it by 1000, then divide it by 125. The result is the dosage in milligrams that you should administer to help deal with your pet’s allergies. An easier way to calculate the appropriate dosage is to give it 8mg of Quercetin per every lb. of its weight.


Colostrum is naturally found in the mother’s milk of all mammals. It is essential for the immune system development of newborns but also contains PRP which can help reduce allergic symptoms. It helps control the immune system which overreacts to allergens and causes all the adverse effects.

It is also anti-inflammatory and will help reduce the histamine which causes allergic reactions in dogs.

You should give 1/3 tablespoon per 25lb. of the bodyweight of the dog twice a day. Administer it before you feed the dog, or feed it to your pup in some broth or yogurt.

Bromelain and Papain

These are proteolytic enzymes that break down the protein and increase the absorption of Quercetin. If you are using Quercetin to treat your dog’s allergy, you should strongly consider giving it bromelain and Papain which will help it work faster and better for relieving the adverse reactions to the allergens.

Oat Baths

If you are sure that the dog has itchy skin due to an allergy rather than a yeast infection, then you can soothe it with a nice oat bath.

All you need to do is to boil oat straw and then add it to the pup’s bathwater.

This will help reduce the itching, and will also help remove any allergens stuck to the dog’s coat or skin.

Aloe Vera

Use only the gel from the Aloe Vera plant or use a commercially available Aloe Vera gel to apply to the affected area. Aloe Vera has strong anti-fungal, antibacterial and anti-inflammatory properties which will help alleviate the itching and irritation of the skin and will also protect it from getting infected by incessant scratching.

Do this twice a day and Fido will start feeling better immediately due to its cooling effect.


If your dog is biting its toes, you could alleviate the itching by applying a fresh or dry thyme infusion to the affected areas. Get the solution in between the toes as well, to make the dog stop biting its paws.

Chickweed Gel

Chickweed is also known for its excellent anti-inflammatory properties, which can help reduce itching and treat any hot spots due to allergies in dogs.

It should be applied to the itchy areas and has an immediate cooling and alleviating effect. It can be used for bug bites, eczema, or other rashes on your pup’s skin.

Apple Cider Vinegar

Use diluted apple cider vinegar to clean your dog’s paws for any stuck pollen on them. You can also use it as an ear cleaner, or spray it on the itchy area for immediate relief.

Do not use apple cider vinegar if the dog has sores or wounds.

Coconut Oil

Coconut oil can be very beneficial for your dog and contains lauric acid which helps decrease the production of yeast. It can help soothe the itching and other allergic reactions to flea bites.

It also has antibacterial and antiviral properties which will help fight infections and boost the pup’s immune system and also help digestive problems often due to allergies.

Related: Coconut Oil For Dog Shedding

Sprouted Seeds

Sprouted seeds contain vitamins, enzymes, minerals, and probiotics which can help improve the health and balance of the gut flora of the dog.

This is essential for controlling the abnormal reaction of the immune system of dogs to allergens.

It will also replace the grass which your dog eats when foraging outdoors.

Start feeding the dog with 1 tablespoon per 10 lbs. of its body weight per day with sprouted seeds which you can sprinkle on its food.


Nettles contain histamine which will help the dog’s body protect itself from allergen attacks.

You can pick the nettles yourself, dry them and make tea with their leaves, or sauté them and sprinkle them on the dog’s food.

You can also apply the tea when cooled down directly on the itchy skin.

If you decide to give your dog a nettle tincture, you should administer 2 drops per 10 pounds of its body weight a day.

Baking Soda

Baking soda can be very efficient for calming red or itchy skin. You can mix a simple paste of a spoonful of baking soda with some water and apply it to the itchy area. Let it sit for a few hours and then rinse it off.

It is especially useful for resolving itchiness on the toes or paws of the dog.

You can also make a baking soda and water spray and apply it to the skin of the dog.


Licorice contains glycyrrhizic acid which has an effect similar to codeine. It can relieve inflammations of the digestive tract and remove the mucus from the respiratory tract.

Start by giving your pup 12 to 20 drops of licorice per 20 pounds of its body weight twice a day. Use low alcohol licorice extract.

If you want to give your dog licorice tea, you should triple the abovementioned dose for the best effect.

Green Tea

Green tea contains polyphenols which have an antihistamine and anti-inflammatory effect and can help soothe itchiness and inflamed skin.

Make a strong green tea brew and let it cool down. Apply it to the itchy areas for up to 10 minutes.

You can keep the brew in the fridge for later applications.

Witch Hazel

Witch hazel contains a lot of tannins which can help reduce swelling or any broken skin. Soak a cotton ball in Witch Hazel and apply it to the affected areas several times a day.

You can use it for itchy ears or dip your pup’s feet in it if it has itchy toes and paws.

Cabbage Leaf

Cabbage leaves can help remove the heat associated with irritation and inflammation of the dog’s skin.

Pound a leaf until its juice has oozed out and hold it on top of the inflamed area.

You will feel how the leaf gets warmer as it absorbs the heat and the inflammation from the skin of your fur baby.

Remove it after a few minutes.

Related: Can I Give My Dog Tums? Is Tums Safe For Dogs?

Final words about Benadryl for dogs

Different treatments are available for dogs with allergies, anxiety, or other health issues which are sometimes treated with the human antihistamine named Benadryl.

Benadryl is safe for use in dogs when given in the appropriate dosage, and only after a vet has recommended or approved its use.

The use of Benadryl has not yet been approved by the FDA, but it is not uncommon for people to choose to give it to their dogs, be it for treating allergies, preventing allergies, as well as for issues like hyperactivity, anxiety, or motion sickness.

Overall, the best way to treat your pup’s allergy is to keep it as far away from the allergen as possible.

Make sure you wash your dog’s paws, wipe its coat and wash its bedding more often when hay fever season starts if it has a pollen allergy.

If it is allergic to a known allergen and it is possible to keep it away from it – then do it.

Dogs with food allergies should be subjected to elimination diets with foods with limited ingredients so that the exact allergen can be identified.

Dogs with flea allergens need to be treated with the appropriate insecticide dog products so that flea infestations and bites are avoided altogether.

Hypo energetic dogs can be worn down with intensive exercise and play, instead of being given medications.

Benadryl can be quite effective in relieving the symptoms of your pup’s allergy, and help prevent their onset, but it does have some adverse effects which can make the condition of your dog even worse, especially if it already has other health issues.

Never give your dog Benadryl without speaking to the vet first, and always choose Benadryl which doesn’t have alcohol or other medications in it.

As a short-term relief, Benadryl can do wonders for your pup, but in the long run, you should work along with your veterinarian to look for the cause, and for ways to prevent these upsetting allergic reactions altogether.

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