Is Benadryl Safe For Dogs?

Benadryl For Dogs
Benadryl … so many people love using this over-the-counter medication for their dogs. Maybe you do too. Conventional vets use Benadryl for dogs and recommend it … for just about anything. Ask your vet about allergies … or anxiety or car sickness or reverse sneezing … and he’ll likely suggest Benadryl. Or maybe you ask for a rabies exemption because your dog had a reaction last time. Your vet says “don’t worry, we’ll just give her a Benadryl before the vaccine.” (More about what’s wrong with this later.) Lots of dog owners view Benadryl as an easy fix for various problems. You’ll see people on social media advising “give her Benadryl.” It could be for a dog with hives, separation anxiety or fear of thunder. But the problem is … Benadryl only hides the problem temporarily. And it’s not safe. So … let’s get into some detail about Benadryl … and why you should choose natural options that are safer and just as effective.

The History Of Benadryl

Benadryl’s a brand name for the drug diphenhydramine hydrochloride. (Let’s call it “DH” to keep it simple!) A chemical engineer named Dr George Rieveschl invented Benadryl in 1943. He was at the drug company, Parke-Davis, now part of Pfizer. In 1946, the FDA approved it as the first prescription antihistamine. DH is also sold under many generic brand names. There’s even a liver flavored pet brand called Vetadryl. It’s an antihistamine drug. It also has anticholinergic (drying) and sedative effects. And because of its sedative effects, DH is in many other over-the-counter drugs. Watch for the ones  with “PM” after their name. Tylenol PM is an example of this – it contains acetaminophen for pain relief, plus DH to make you drowsy.

What Antihistamines Do

As the name suggests, antihistamines counteract the effect of histamine. Histamine is a natural body chemical with a few useful roles:
  • It’s a chemical messenger in the nervous system.
  • It’s a part of gastric acid that helps the digestive process.
  • It helps dilate blood vessels, part of the body’s immune response to pathogens.
But too much histamine can lead to allergic reactions, food sensitivities and more. Histamines can damage capillaries. This lets blood plasma leak into body tissues … and leads to itchiness, redness and inflammation. So vets and doctors prescribe antihistamines that block the body’s histamine receptors. Like other first-generation antihistamines, DH specifically blocks H1 receptors in the brain. But that can cause problems … because suppressing the body’s natural healing response isn’t a good long-term plan.

Symptoms Are Natural Healing

Your dog’s symptoms are her body’s way of healing. So vets see something like itching, sneezing or hives and give Benadryl.  And the problem goes away … or seems to. Unfortunately, removing the symptoms doesn’t get at the root of the problem. The underlying disease causing the itching is still there. So the itching will keep coming back. Eventually your vet will prescribe other drugs … like antibiotics or steroids. But your dog still has the ongoing problem. Another problem with suppressing symptoms is that it can drive the disease deeper. And then it comes back … sometimes in a more serious form.  And now, the disease is chronic. Holistic vets have many stories about dogs treated with “anti-” drugs. Many of them end up with problems like seizures, emotional issues, or even cancer. So that’s one problem with using Benadryl … it doesn’t cure anything. It just hides the symptoms for a while. What about other side effects?

The Side Effects Of Benadryl For Dogs

Benadryl may seem like a harmless option. But it has quite a long list of possible side effects.  In fact, the Canadian Society of Allergy and Clinical Immunology has given serious warnings about them, even for people. The organization issued a 2019 position statement about Benadryl. They advised against the drug because of the high risk of side effects and overdose. They said the drug leads to …
“…several intolerable and potentially life-threatening adverse effects.”
They explained that antihistamine drugs cross the blood–brain barrier
“… and may lead to significant CNS suppression and toxicity resulting in psychomotor impairment, coma, and even death.”
So that’s rather scary. And so’s the list of adverse effects. Some of the more serious ones are from long term use of the drug.
  • Dryness of mouth, nose and throat
  • Drowsiness
  • Low blood pressure
  • Heart palpitations
  • Cognitive issues, confusion, dementia
  • Anxiety
  • Moodiness
  • Depression
  • Trembling
  • Chemical dependence
  • Nausea
  • Vomiting
  • Change in appetite
  • Constipation
  • Can mask symptoms of gastrointestinal problems
And you can easily overdose your dog with Benadryl … with dire results.

Risk Of Overdosing Benadryl For Dogs

If you do give Benadryl, don’t guess at the dosing. Talk to your vet to find out how much to give. Because Benadryl overdose can really harm your dog. The dosing of Benadryl for dogs has a narrow safety margin. If you give your dog too much Benadryl, you may see serious symptoms like …
  • Red eyes or dilated pupils
  • Intense drowsiness
  • Rapid heart rate
  • Difficulty breathing
  • Aggression
  • Fever
  • Seizures
  • Muscle tremors
  • Lack of coordination, inability to walk
  • Difficulty urinating
  • Delirium
So … if you’ve given your dog Benadryl and you see these symptoms, get to the emergency vet.

Dogs Who Should Never Take Benadryl

Dogs with these conditions should never take Benadryl (or other DH drugs):
  • Glaucoma
  • Heart failure
  • Prostatic hypertrophy
  • Seizures
  • Allergic lung disease
  • Bladder neck obstruction
  • Hyperthyroid (rare in dogs)
Always ask your vet about interactions with other drugs your dog may be on. For example, anxiety medications don’t combine well with Benadryl.


If you do use Benadryl for dogs, follow these rules:
  • Don’t try to guess the dose by yourself. Ask your vet how much to give.
  • Don’t ever give liquid Benadryl. You might assume that because it’s made for children, it’s safe. But you’d be wrong. It’s full of harmful chemical ingredients and dyes.
  • Always read the ingredients of the product you buy. Don’t buy formulas that contain Xylitol, which is deadly to dogs. Avoid formulas with dyes.
  • Don’t give it to pregnant or nursing females.
But hopefully … after reading these risks, you’ve made the right decision. and that is to use natural alternatives to Benadryl for you dog.

Natural Alternatives To Benadryl For Dogs

So … here are some conditions people use Benadryl for … and natural options you can use instead.

Benadryl Alternatives For Allergies And Skin Problems

Allergies are complicated. If your dog has any kind of allergy issue you’ll need to figure out what’s causing the problem. Your dog may have:
  • Itchy or irritated skin
  • Hives
  • Hotspots
  • Ear infections
  • Digestive issues
  • Chronic diarrhea
It could stem from things like …
  • Food
  • Medication
  • Pest control products
  • Vaccination
  • Yeast infection
  • Seasonal allergies
  • Environmental toxins
  • Autoimmune disease
… or other causes So … you’ll have to do some detective work. You may need a holistic vet’s help in getting to the bottom of the problem. (Hint: don’t ask a conventional vet. He’ll almost certainly prescribe suppressive drugs. These might include Benadryl, Apoquel, Cytopoint, antibiotics or steroids). Once you’ve nailed down the issue, you can start to make changes that’ll help. And you can try some natural supplements that help with allergies. Instead of those drugs, consider natural options like these.


Colostrum is the substance in mother’s first milk that helps build the newborn’s immune system. And it can help your dog’s immune system deal with allergies. Colostrum is most effective with environmental and seasonal allergies.  Give your dog 1/3 tsp powdered colostrum per 25 lbs of body weight, twice a day.


If you want an alternative to Benadryl, consider quercetin. In fact, quercetin is often referred to as as Nature’s Benadryl. That’s because it’s a natural antihistamine that can stop the body from releasing histamines. Quercetin is naturally in foods like berries and apples (especially with the skin on). You can also buy a quercetin supplement at a health food store. Give your dog 80 mg of quercetin powder per 10 lbs of body weight.

Medicinal Mushrooms

Mushrooms are another food that can help boost your dog’s immune response. That’s because of the main medicinal property, beta-glucan. Beta-glucans change certain immune cells, helping to prevent the allergic response and inflammation. It activates other immune cells that help remove unwanted substances from the body. The mushrooms with the highest beta-glucan content are: If you give your dog whole mushrooms, be sure to cook them. Raw mushrooms are quite indigestible. Or buy a mushroom supplement. There are two things to look for in a mushroom supplement:
  1. Check the certificate of analysis to make sure it has at least 30% beta-glucan content.
  2. Make sure your mushrooms are whole mushrooms, not just mycelium. Mycelium is only part of the mushroom; it’s grown on grains, making it much higher in starch and lower in beta glucans.

Alternatives For Bee Stings And Insect Bites

Insect bites and stings are another ailment people use Benadryl for. But there are much better options.

Fast Remedies For Insect Stings

If you’re out in the woods with my dogs in the summer, there are a couple of really good homeopathic remedies to carry …
  • Ledum palustre (30C or 200C): an effective remedy for most insect stings or puncture wounds.
  • Apis mellifica (30C or 200C): this remedy works well for allergic reactions. It helps with stings or red or swollen bites.
Dogs might step on a ground hornet or get a bee sting on the face. One of these remedies will usually bring down the pain and swelling right away.
  • Try Apis first if the sting becomes very swollen and red, with lots of itching and even pain.
  • Try Ledum first if the bite area is cold and puffy.
To give homeopathic remedies, follow the instructions in this article >>

Plaintain – More Than A Weed!

A great herbal remedy for insect bites is one you might find whenever you’re out walking. You may consider it a weed in your back yard … but plantain is a great way to treat insect stings in an emergency. The juice of the plantain leaf is what you’ll need to soothe the sting. The easiest way to do that is chew it a little to release the juice, then rub the leaf on the sting. Reapply as needed.

Natural Alternatives To Benadryl For Anxiety

Whatever causes anxiety … it may be separation anxiety or fear of thunder or fireworks … your vet will often suggest Benadryl for your dog. Because of its sedative effects, it can help calm your dog. Instead, consider one of the many natural solutions for anxiety. There are many options … including herbsflower essencesessential oils, and homeopathy. But one of the most effective remedies for your dog’s anxiety, whatever the cause … is CBD oil.

CBD Oil For Anxiety

CBD oil for dogs comes from the hemp plant. It has similar calming effects to marijuana … but without the THC that gets people high. And now there are studies showing CBD has anxiolytic (anti-anxiety) effects. You can give CBD oil for dogs … and the most common side effect is that he might get a little sleepy. Buy and organic, full spectrum CBD oil with a full range of cannabinoids: CBD, CBA, CBC, CBN and CBG. These all work together for the “entourage effect.” The general rule for dosing CBD is to give your dog 1mg to 6mg of CBD per 10 lbs of body weight. (You’ll need to check how much actual CBD is in each dropper of the oil you buy).

Motion Sickness

If your dog gets queasy in the car, there are lots of things to help him. Your vet might recommend Benadryl, or even Dramamine. But try one of these solutions instead.


Most dogs will outgrow motion sickness. So start by taking your dog for lots of short rides around the block. Or take him somewhere fun like the park. That way he should start to expect a fun time when he gets in the car … instead of worrying about a trip to the vet or groomer. Being anxious in the car will make him more likely to get carsick.


Ginger, peppermint or fennel are all good herbs for nausea. You can make a tea from one or more of these herbs. Let it cool, and give some to your dog about 30-60 minutes before getting in the car.  Give 1 Tbsp per 20 lbs of body weight.

Flower Essences

If your dog’s nausea is due to anxiety, flower essences can help. Try giving him the combination flower essence Rescue Remedy before each trip. You can give it as often as needed. It’s calming, gentle and has no side effects.


Several homeopathic remedies can help with car sickness. Choose the one that best fits your dog and give it 30 to 60 minutes before a car ride.
  • Nux vomica 30C: often used for digestive problems, Nux can also help a carsick dog. It may stop him from vomiting in the car.
  • Sepia 30C: if your dog feels anxious about getting in the car, this remedy can cheer him up. It’s an especially good remedy for senior dogs.
  • Cocculus indicus 30C: This remedy works well for a dog who seems to get worse when you open the car window! So don’t let the fresh air in for a dog like this.
  • Tabacum 30C: Use this remedy for a dog who thinks a car ride means something unpleasant … like a trip to the vet.
To give homeopathic remedies, follow the instructions in this article >>

Mast Cell Tumors

Conventional vets often give Benadryl to dogs with mast cell tumors (MCTs). Because MCTs cause excess histamine in the body … Benadryl can help control that response. But once again, that’s just a short-term solution that suppresses your dog’s natural healing. Canine herbalist Rita Hogan recommends several herbal treatments for your dog’s MCT. These include:
  • Ashwaganda
  • Astragalus Root
  • Burdock Root
  • Calendula or Cleavers
  • Dandelion Root and Leaf
  • Echinacea
  • Maritime Pine Bark
  • Nettles
  • Red Clover
  • Sweet Violet
Read Rita’s advice on how to use these herbs for mast cell tumors here.

Reverse Sneezing

It’s hard to describe reverse sneezing … but you might find it quite alarming to see your dog do it. It’s not really a sneeze … but more of a series of spasmodic inhalations. Your dog may make some snorting or gagging noises. He might hang his head low and look unhappy. Conventional vets view reverse sneezing as an allergic response. They often suggest massaging your dog’s throat to help stop the spasms … or covering the nostrils to make your dog swallow. And they’ll also tell you to give your dog Benadryl, to suppress the reverse sneezing response. But once again, Benadryl only covers up the symptoms. It doesn’t fix the problem. Reverse sneezing is often a chronic condition … but all kinds of things can trigger it. Some dogs do it when they’re stressed. In many dogs it’s a sign of vaccinosis … due to over-vaccination. Homeopathic vets know that reverse sneezing usually stems from rabies over-vaccination.  Rabies vaccinosis often causes rabies-like symptoms. Rabid animals can experience jerky breathing or throat spasms.  In a dog with rabies vaccinosis it shows up as reverse sneezing.  It’s quite common in toy breeds as well as brachycephalic dogs … but other breeds do it too. For reverse sneezing it’s best to consult a homeopathic vet. He’ll analyze your dog’s symptoms and prescribe an appropriate constitutional remedy. In this article, homeopathic veterinarian Dr Ronna Kabler explains rabies miasm. She mentions some remedies homeopaths use to treat rabies vaccinosis symptoms in dogs. You can find a homeopathic vet at the Academy of Veterinary Homeopathy. Most will do phone consults … so they don’t have to be local.

Acute Vaccine Reactions

Earlier we mentioned that your vet might suggest giving Benadryl before vaccination. This usually happens if your dog’s had an acute vaccine reaction in the past. Acute refers to reactions that happen fast … within the first hours or days after vaccination. This type of reaction can be serious. It might be facial swelling or fever … which are unpleasant but manageable. But it could be really serious … causing anaphylactic shock or even death. There are homeopathic remedies that can help with vaccine reactions. But the real solution is: don’t take the risk. If your dog’s ever had a vaccine reaction before, there’s a higher chance it’ll happen again. The answer to this problem is not “give Benadryl” … or some other remedy to try to prevent the reaction. The answer is: don’t vaccinate your dog again if he’s had a reaction in the past! Don’t let your vet do it. Find a different vet if you have to. And try not to use Benadryl for dogs, now that you know about the risks as well as some natural options! de Mello Schier AR et al. Antidepressant-like and anxiolytic-like effects of cannabidiol: a chemical compound of Cannabis sativa. CNS Neurol Disord Drug Targets. 2014;13(6):953-60.

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