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Marijuana Toxicity in Pets: A Growing Problem With Serious Consequences

As laws change and the use of this drug becomes more prevalent, marijuana toxicity in pets is on the rise. Edibles with chocolate are the worst.

Marijuana Toxicity in Pets
Yes, marijuana and cannabis edibles can be toxic for pets — and even deadly in rare cases. It’s no laughing matter. Photo: Sonja Rachbauer

As the movement to legalize and decriminalize marijuana has grown in recent years in the United States, marijuana toxicity in pets has been on the rise. As of 2020, more than half of states have passed laws to either fully or partially decriminalize possession offenses.

It’s no coincidence from 2018 to 2019, the ASPCA’s Animal Poison Control Center reported a whopping 765% increase in marijuana cases involving pets. This is a nationwide trend.

Now, with sales of cannabis edibles shooting through the roof during the COVID-19 pandemic, marijuana toxicity in pets is a more important topic than ever before. Here is what you need to know.

Marijuana Toxicity in Pets

I first wrote this article in 2014, back when I owned a rural veterinary practice. By coincidence, right after I started writing that original draft, I saw the worst emergency case of marijuana/chocolate toxicity in a dog I had ever seen as a veterinarian.

My new little patient had multiple strikes against him:

  • A small, 14-pound dog …
  • Who had eaten a large amount of dark chocolate brownies …
  • Which were loaded with hashish …
  • And his caretakers didn’t realize this until they found him comatose, about 15 hours later. Yikes.

Even if his folks had not told me what he had gotten into, the little dog’s breath was a dead giveaway. He reeked of marijuana. I had never smelled this strong of a pot smell on a dog before.

The good news? The midnight brownie bandit recovered fully. He saved his own life by vomiting up a large amount of his hash bash, and then we supported him through his detox phase.

Here’s a quick video of my patient:

YouTube player

How Serious Is It If My Pet Ingests Marijuana?

Thankfully, veterinarians can usually relax and laugh — a little — when we see “a party animal” fall into our hospital.

Marijuana has a “wide margin of safety,” meaning it takes a great deal of the substance to be lethal. “There’s nothing about that actual drug itself that will kill them,” says Dr. Dorrie Black, DVM, MPVM. “It doesn’t cause any organ failure. It doesn’t cause liver failure, renal failure.”

But that doesn’t mean it isn’t a serious concern. “Pets don’t get stoned — they get poisoned,” says Dr. Mark Liberto, DVM.

In a few cases, small dogs have died after ingesting large quantities of food containing marijuana:

  • If a dog eats an entire tray of brownies containing marijuana or hashish, the situation is potentially life-threatening.
  • Even so, deaths are extremely rare cases where people have not been around to notice the emergency. These intoxicated dogs probably could have been saved with medical intervention and support.

“There may be additional toxic ingredients involved — such as chocolate, raisins or xylitol — which result in a poorer prognosis. Cats may also directly consume the plant material,” says the American Veterinary Medical Association (AVMA).

Also, be aware that the drug can sedate a pet so fully that they end up inhaling their own vomit (aspiration), which can be deadly.

“If you know or suspect your pet of having been exposed to any form of cannabis, please consult your veterinarian immediately,” the AVMA advises.

Signs of Marijuana Poisoning in a Dog or Cat

  • Dilated eyes
  • Drunken appearance
  • Stumbling

Sound familiar?

If you are chilling with your pet, the pair of you will look just about the same. Your pet may also vomit, become agitated, or exhibit urinary incontinence or urine dribbling.

Here’s a deeper look at the signs of marijuana toxicity in pets:

  • Mydriasis. This term describes dilated pupils. Think of that glassy-eyed, dull but staring sort of look when someone is under the influence.
  • Somnolent. This word is borrowed from human medicine when describing a patient with altered consciousness. Somnolent means the individual can be easily aroused but requires stimulation to stay awake. In other words, your stoned pet is continually nodding off. Somnolent is the state between lethargy and obtunded (unable to rouse).
  • Head weaving at rest and listing. Dogs under the influence of marijuana are rolling their heads around and listing to one side or the other when trying to walk (ataxia). In other words, they look like a cartoon drunken sailor.
  • Dribbling urine. Unlike many other toxicoses, pot almost always makes a pet dribble urine uncontrollably. If we notice this, marijuana should be high on the list of suspects.

With any luck, you yourself are not in the same condition, so you can get your dog or cat to the vet right away.

Marijuana Toxicity in Pets
Cannabis edibles and baked goods, especially those containing chocolate, are a major culprit in marijuana toxicity in pets. Photo: valtercirillo

Diagnosing Marijuana Toxicity in Pets

The intoxicated state of the pet is a big clue. But other, more serious toxins can create the same signs.

“As the attending veterinarian, I consider the possibility of other factors contributing to the overall picture of health or illness,” says Dr. Patrick Mahaney, VMD. “Did the pet consume only cannabis? Could prescription or over-the-counter human or veterinary medications, other recreational drugs, or unknown intoxicating substances be involved?”

Being completely up front and honest with your vet is a great help, but many people are too embarrassed to admit to the marijuana. “Most are somewhat reluctant to share the truth, but ultimately concede under gentle, direct questioning,” says Dr. Mahaney.

If the person is truly unaware of any drug exposure, there is a quick toxicology screen available to vets that tests for cocaine, THC (the psychoactive ingredient in marijuana), opiates, methamphetamines, benzodiazepines and oxycodone. Being able to identify the drug helps us in treatment.

If the pet tests positive for THC and a non-pot-smoking pet parent has brought the pet in, then an unpleasant conversation will be taking place when their teenager gets home from school.

How Toxic Is Marijuana to My Pet, Really?

Officially speaking, there is no safe level of exposure. But, all in all, ingestion of marijuana by a pet is fairly safe — at least compared with other drugs.

Most pets get into marijuana accidentally. They find the bag of weed, partially smoked joint, gummies or brownies and then proceed to binge. If you’re honest and knowledgeable about the amount and source of the drug, it can help your vet a great deal with the treatment plan.

Occasionally I have had some kids get their dogs high deliberately, and this is just stupid. Unfortunately, people who exhibit this level of irresponsibility are probably not going to take their intoxicated dog to the vet.

Hopefully their pet will be able to sleep off a small amount of marijuana without serious side effects, such as seizure or coma, while everyone else continues to party.

Treatment of Marijuana Toxicity

Onset of symptoms after ingesting or inhaling marijuana is 30–60 minutes in most pets. Depending on the dosage and strength of the drug, these symptoms can last 18–36 hours. (Yes, up to a day and a half.)

If we have an intoxicated pet, supportive care is all we can do. There is no antidote to reverse the effects of marijuana. Basically, the pet just has to sleep it off under supervision.

Treatment may include:

  • Activated charcoal to absorb some of the toxins
  • IV fluids
  • Anti-vomiting medication
  • Temperature regulation
  • Controlling seizures or tremors

“Having treated innumerable cannabis toxicities, I feel comfortable that my patients will make a full recovery with the appropriate care,” says Dr. Mahaney.


Some clients have told me they were reluctant to “come clean” about their pet’s marijuana ingestion because they thought I would report them to the police.

Veterinarians have nothing to do with reporting your use or your pet’s marijuana use to the authorities. “The veterinarian is not under obligation to report the owner/client to the police, and it is better for all involved to treat the animal appropriately,” says VRCC Veterinary Specialty and Emergency Hospital of Englewood, Colorado, a state that legalized recreational marijuana in 2014.

Actual animal abuse is a different story, and, yes, vets are responsible for reporting abuse — but accidental marijuana ingestion does not qualify.

Marijuana Toxicity in Pets
Nodding off and listing to the side are among the symptoms of marijuana toxicity in pets. Photo: manfredrichter

Another Case

My veterinary clinic once had a young person bring in her adorable little terrier mix for staggering and strange neurological behavior.

After taking a look at the dog’s dilated, glazed eyes and observing his strange pattern of walking, we had our suspicions.

“No, I don’t think he could have gotten into anything. There’s nothing around,” she told us. “We watch him like a hawk. He woke up like this.”

After about an hour, the teetering terrier seemed quite a bit better.

I took him out for a little walk to assess his neurological status. He seemed somewhat uncomfortable in the rear end and stooped to poop. With some difficulty, he pooped out some large cocktail almonds, at which point he seemed much happier.

I believe this pup partook in someone’s pot the night before and then found some snacks to satisfy his munchies. Within a few hours, he was as good as new.

Final Thoughts

Although marijuana has a large safety margin, it can still make your dog or cat quite ill and neurologically impaired.

Baked laced goods seem to be much more of a danger. Where the human party animal might have 1–2 brownies and call it a night, the canine party animal will eat the entire tray. This can be very toxic.

There are more marijuana edibles around than ever before, so please keep your pets away from them.

And assume nothing about visitors. Old Uncle Morton just might have some weed in his coat pocket that could mean a trip to the emergency vet if your dog gets into it.

CBD oils and edibles are not completely off the hook, either — there have been documented reports of pets developing THC signs after ingesting CBD products. Please be careful with these, too.

Even medical marijuana is a complicated topic among veterinarians. For more on that, see my article “When Will Medical Marijuana Become Legal for Pets?”


vet-cross60pThis pet health content was written by a veterinarian, Dr. Debora Lichtenberg, VMD. This article was originally published in 2014 and is regularly updated. It was last reviewed for accuracy and updated July 14, 2020.

If you have questions or concerns, call your vet, who is best equipped to ensure the health and well-being of your pet. This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. See additional information.