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Euthanizing a Dog at Home With Benadryl? Risks & Vet Advice

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This article was updated on April 23rd, 2022

Euthanizing your dog is unquestionably one of the most difficult times as a dog owner. You’ve spent so much time together, and it’s time to say goodbye.

On top of the emotional stress, a lot of dog owners also face expensive vet bills, making the process even more challenging. Not everyone can afford these expensive bills piling up.

As a result, many owners are trying to find inexpensive options to euthanize their dogs, or ways to humanely euthanize a dog at home and want to figure out how to euthanize a dog with a simple over-the-counter product such as Benadryl.

While Benadryl can indeed be lethal to dogs, there are several very important legal and medical factors that you should consider. We will explain in this article why you should not use Benadryl, and what to do instead.

Summary of key points:

  • It is estimated that Benadryl can be lethal to dogs at 24 to 30 mg per kilogram of body weight by IV administration. Note that the impact of “oral” diphenhydramine in dogs has not been studied, and this estimate is extrapolated from studies on other animal species (read below for important details).
  • Benadryl is lethal to dogs because it can cause serious neurological and cardiovascular effects – it is NOT a comfortable way for your dog to pass away, and we recommend other options.
  • In most US states, dog euthanasia can often ONLY be performed by a veterinary professional. A very small number of euthanasia methods are allowed and deemed safe for your dog (read below for details), and it may not be legal to use Benadryl in your location.
  • Dog euthanasia at home is allowed in most states in the US, but regulation still often requires that it should be performed by a veterinary professional.
  • Make sure to read our page listing low-cost options to put a dog down (veterinarian options).

DISCLAIMER: This website does not provide legal advice in any shape or form. Please consult your lawyer for any legal advice.

Can Benadryl Help Euthanize a Dog?

Benadryl is an inexpensive over-the-counter antihistamine medication used to treat allergies. The active component in Benadryl is called diphenhydramine, which comes in tablets, capsules, or liquid. Benadryl can indeed be lethal to dogs when given at high doses. It should only be administered to dogs in certain circumstances with the supervision of your veterinarian.

WATCH: 3 Important Tips To Care For an Old Dog [VET VIDEO]

A recommended dose for the treatment of mild allergies or anxiety for most healthy adult dogs is approximately 2 to 4 mg per kilogram of body weight, but this can vary based on your dog’s health profile. For a dog weighing about 40 pounds, this would equate to 36 to 72 mg diphenhydramine or 1 to 1.5 tablets (for tablets with 50mg diphenhydramine). Make sure your consult with your veterinarian to determine the right amount for your dog. So what dose is then lethal to dogs?

According to this scientific paper, the lethal dose for diphenhydramine in dogs ranges between 24 to 30 mg per kilogram of body weight by IV administration. For a 40-pound dog, this would equate to about 430 to 540 mg, or 9-10 tablets (for tablets with 50mg diphenhydramine – note that some tablets are 25mg only).

However, it is important to note that the impact of “oral” diphenhydramine in dogs has not been studied (only “IV” diphenhydramine), and these estimates are derived from extrapolated values from other animal species. The unpredictability of dosage is one of the many reasons that euthanizing a dog with Benadryl is not allowed in most situations.

Because Benadryl can have dramatic side effects for your dog, they can suffer a lot before the active ingredient actually results in death, especially if the dose is too low. We recommend visiting the AKC site to learn important details about Benadryl and dogs.

Why you Should Not Euthanize a Dog at Home with Benadryl

Besides possible legal ramifications depending on your location, Benadryl is also a terrible way to euthanize a dog. The reasons include:

1) There are significant effects that could cause unnecessary pain and suffering for your dog. Benadryl is lethal to dogs because it can cause serious neurological and cardiovascular effects, with effects including hyper-excitability, rapid heartbeat, seizures, convulsions, or respiratory failure.

As a result, using Benadryl to euthanize your dog has many risks to create a painful and stressful death for your dog, and a veterinarian professional needs to be consulted to review other options. There are much more humane ways to euthanize your dog.

2) The exact amount to be ingested is unknown and can vary significantly from dog to dog. The scientific paper referenced earlier estimated that as few as 2-4 tablets could have very adverse and even lethal effects to a dog. However, the paper also noted a case where a dog survived with treatment, even after ingesting 67 mg per kilogram of body weight (as many as 20+ tablets at 50mg/tablet, for a 40-pound dog).

There is simply no good data to estimate the dose required to euthanize a dog with Benadryl, with potential dire consequences for your dog. With such an unpredictable lethal dose, Benadryl is far from the best option to use for euthanizing a dog. Additionally, it may not be legal to do so in your location. Please read the next section for more details.

As a result, we recommend that you consult with your veterinarian to discuss options.

Disclaimer: This content is not a substitute for veterinary care. Always consult with your vet for health decisions. Learn more.

The Humane Society offers lower-cost options to put your dog down. Read our page listing low-cost options to put a dog down

Are You Allowed to Euthanize a Dog at Home? Are You Allowed to Use Benadryl?

Dog euthanasia in the US is highly regulated and can often ONLY be performed by a veterinarian professional or euthanasia technician in most states, to ensure a pain-free and effective process for the animals (with exceptions in case of emergencies). states that “obtaining and administering a fatal dose of euthanasia drugs to your animal without specific training or required license may be a violation of the law.” (Learn more).

Dog euthanasia at home is allowed in most US states, but regulation generally restricts who is allowed to perform the euthanasia to ensure that the process is done in the most humane way possible for your dog. In most states, at-home euthanasia still needs to be performed by a veterinarian professional.

Additionally, only certain euthanasia methods are legally allowed. In most states, the use of Benadryl to euthanize a dog is NOT allowed. Only experts with the appropriate training and licenses may euthanize an animal using barbiturate medicines, such as sodium pentobarbital.

Barbiturate medications are a much more humane way to euthanize an animal. They have been proven to induce a quick and peaceful death that causes no distress to your dog.

If you live in the US, you can view regulation by state on the American Veterinary Medical Association website: State Animal Euthanasia Laws. Please note that our website does not give any legal advice and we are not legal professionals in any way, shape and form: check with your state or lawyer for most recent laws.

DISCLAIMER: This website does not provide legal advice in any share or form. Please consult your lawyer for any legal advice.

What is the Best Way to Euthanize a Dog?

To euthanize a dog, a veterinarian will often use barbiturates to stop a dog’s heart. The medication is administered through an intravenous catheter or an injection. Sometimes, veterinarians will give the dog a sedative first to help make the process pain-free for the dog.

If you are looking for ways to euthanize your sick, injured or elderly dog in the most pain-free way possible, please contact a veterinarian to discuss options.

Euthanasia should always be viewed as a blessing – to be able to stop an animal’s suffering is a wonderful thing. But it must be performed in the right way, with the correct medication, your beloved pet deserves nothing less.  

How To Decrease the Costs of Putting a Dog Down?

We recommend that you read our page listing all the low-cost options to put a dog down.

You can also learn more about dog euthanasia and read our article “is there a way to humanely euthanize a dog at home?


  • Dr. Winnie, Veterinarian

    Dr. Winnie earned a Master in Biology from St Georges University, and graduated from the University of Pretoria's Veterinary School. She is a full-time Veterinarian specializing in internal medicine for companion animals.


  1. Vets are the best choice.. IF you can afford it. So poor or low income people with old or sick pets are just SOL ? … Not everyone can afford a vet these days.. so only people with money should have pets? That’s like saying only people with money should have children.. But then there is Gov Assist for poor families.. No such thing for pets. My cat is 20 years old with severe arthritis and possible cancer. 20 years ago I had the money, she was always Well taken care of.. now I am a single mother and struggling financially.. I cannot afford to have a vet put her down ..let alone comfortably at home.. when I can barely pay rent .. what am I supposed to do? Just let her suffer until she dies?

    • RJ, I’m so sorry to hear that your cat is uncomfortable. Many veterinarians will compassionately euthanize a pet for free. You will have to make your own accommodations for aftercare, but our number one goal is to make pets comfortable and alleviate suffering.

  2. IF you can find a veterinarian willing to euthanize your pet. My dog’s pain and suffering is worth a lot of money to the veterinarians in this area. I can easily afford to pay to have him properly euthanized, but I can’t get a veterinarian or a shelter to do it. He has horrific arthritis, it takes a combined effort of Meloxicam and gabapentin to even take the edge off of his pain, and even that doesn’t take his pain away. He has pain relieving eye drops for his glaucoma, he’s blind in both eyes. He’s 11 and 1/2 years old and he has spent the last year in a drugged up stupor 24 hours a day because no one will ” euthanize a healthy dog.” A healthy dog that has so much pain that he has to be kept sedated around the clock, who only wakes up long enough to vomit, who isn’t strong enough to stand up and get out of his own feces. Healthy dog my foot!
    Healthy paycheck for the veterinarians is what he is.
    He has no life threatening illnesses, so they’re milking his pain for all it’s worth.

    • I’m so sorry you’ve had bad experiences with end-of-life care and your current veterinarians. Arthritis is painful as is glaucoma, and it sounds like your dog is uncomfortable. If your veterinarians will not consider euthanasia, there are reasonable alternatives like the humane society or in-home hospice vets. I would reach out to those resources.

  3. NEVER do this. Under ANY circumstances. IT DOES NOT WORK.
    My 14 year old German Shephard was hit by a car, he had terrible arthritis, hip dysplasia and was in general end stage health. I knew he would never recover from the hit and run so I made the heart wrenching choice to put him down.
    I tried every home euthanasia company around NW Georgia only to be told they could not make it to me in less than three or four days and my local vet said I would need to bring him in. YOU try wrangling a 130 pound severely injured dog into a truck. Needless to say, that wasn’t a possibility.
    I opted for the Benadryl approach. I did all the research to make sure I was giving my boy the correct dose for a large dog. I actually gave him FIVE times the correct dose in pill form and three times the correct dose in liquid form. What should have been enough per EVERY post and website I found in the internet to kill a horse.
    All it did was caused him agonizing pain and severely jacked with his nervous system. He had terrible seizures all night and screamed in pain throughout the night. This went on for 14 hours. At 6am the following morning I put a pistol to my best friends head, begged for his forgiveness and pulled the trigger to end his suffering , SUFFERING THAT I HAD CAUSED. My only solace is that the bullet was instantaneous, but I buried my head in his massive shoulder and cried like a baby for a full thirty minutes begging him to forgive me for what this had brought me to. THIS WILL HAUNT ME FOR THE REST OF MY LIFE AND BECAUSE OF IT I WILL NEVER HAVE ANOTHER DOG. I DO NOT DESERVE ANOTHER DOG. I am only posting this in hopes that it will save someone and their best friends the same agonizing grief.

    • I am so very sorry you had to do this but please don’t blame yourself cause you know deep in your heart, you had no choice. I had to make the same choice a few years ago but thankfully one of my sons were here. Now I’m going to have to make the choice again but thankfully I will have the time to get him to the vet. Hardest thing in the world to do but I have had almost 16 years with him and I would not change a thing.

    • Thank you for sharing this. I was going to try to euthanize my 16 yr old dog at home with benedryl but I won’t now. Brutal and heart wrenching as it is you definitely made the right choice. You gave your beloved pet a mercy.

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