Home News and Features A Bad Trip: Veterinarians are Seeing Dogs Made Ill by Marijuana

A Bad Trip: Veterinarians are Seeing Dogs Made Ill by Marijuana

Ellen Drysdale, Mookie, and Bob Squires, at their home in Berlin. Photo by John Lazenby.
Mookie, a seven-year-old golden retriever, is a very good boy — attentive, handsome, friendly, and engaging.

But Mookie is a dog, and dogs will get into things. What Mookie got into on Monday, April 22, led to a week of anguish for his people, Bob Squires and Ellen Drysdale, of Berlin, who feared they might lose him. Over five tension-filled days he was treated and monitored by veterinarians at a central Vermont animal hospital and Burlington Emergency and Veterinary Specialists (BEVS) in Williston. Not inconsequentially for Bob and Ellen, their vet bills added up to $6,643.10.

Mookie had ingested cannabis in a form his owners cannot identify, because it wasn’t theirs and it wasn’t in their house. Cannabis poisoning in pets —primarily, but not exclusively, dogs — is a phenomenon veterinarians are seeing ever more frequently.

“When we were at BEVS, they said there were four other (similarly afflicted) dogs there that night,” Ellen Drysdale recalls. 

Alison Cornwall, DVM, one of the veterinarians at Onion River Animal Hospital (ORAH), in Berlin, finds that telling. “They’re going to see the worst cases at BEVS,” she says, “because all of us regular folks at non-emergency clinics are going to see the regular cases; it’s when it gets bad that they’re going to go there.” (BEVS, unfortunately, did not respond to requests for an interview.)

No one has documented a direct connection between cannabis legalization in Vermont and the rising incidence of cannabis poisoning in pets. We are left to infer it. However, a 2021 study by researchers in Ontario, Canada, drew a brighter line between the two. Their paper, published online in 2022 by PLOS One (the Public Library of Science), detailed the results of a survey of 251 veterinarians on both sides of the border. It read, in pertinent part:

“Statistical analysis of the survey responses showed that the number of cannabis poisoning cases jumped significantly in both the U.S. and Canada following the 2018 legalization of cannabis in Canada.” As it happens, 2018 was also the year Vermont began its legalization trajectory, first by legalizing private consumption and cultivation for non-medical use (which was already legal), then moving to a regulated public market in 2022.

The Ontario study did include caveats: Pet owners may have become more forthcoming with their veterinarians after possession and use were allowed. Veterinarians, of course, can determine on their own, by testing, whether an animal’s illness is caused by THC (tetrahydrocannabinol, the active ingredient in marijuana), but they, too, may have become more willing to share information with researchers once their customers were safe from prosecution.

Nevertheless, the Ontario study provides strong support for the supposition that now that pot is legal there’s more of it around, or it is being kept less clandestinely, or both. Thus it follows that it’s more environmentally present. For Mookie is far from the only dog whose owners can’t identify exactly how their dog came to consume it. 

Ruth Einstein and Bryan Pfeiffer, who live close to the North Branch River in Montpelier, had an experience with their English shepherd, Odin, four years ago — before retail weed was legal — that may have been a harbinger of the trend.

“He was this really high-energy puppy, about seven or eight months old,” Ruth recounts. “I took him for a walk down by the edge of the river, where there’s a great little cove where people go and hang out. I wasn’t paying much attention, but I saw him grab something and eat it. I wasn’t concerned; he’s a dog; that’s what they do.”

About a half hour after they got home Ruth found Odin overdosed in the back yard, comatose. “He had peed all over himself.”

They had bought Odin from an emergency-room veterinarian in Hanover, New Hampshire. Ruth FaceTimed her, and she recognized the symptoms immediately. “Definitely, it sounds like marijuana.”

Ruth was puzzled. She and Bryan are past their days as pot users, and there was none in the house. It must have been Odin’s little snack down by the river.

Odin’s story ends happily. Following instructions, Ruth put him in a cool place and sat with him the rest of the day. By evening he was okay.

“But it’s one of those things,” she says, “that until it happens to people they aren’t really aware of. Odin is a quick learner,” she adds, “and one of the things we taught him right away was, ‘Leave it!’ That works.”

A Case-By-Case Basis

Not all dogs get by so easy. 

“Treatment of cannabis intoxication varies tremendously, depending on the seriousness of the case,” says Alison Cornwall of ORAH. “Mild cases may require monitoring only. Severe cases can require diligent, multi-day intensive-care support, including IV fluids; breathing, blood pressure, and temperature support; and infusions of products that absorb the THC circulating in the blood and improve excretion of the drug.” Mookie received lipids to improve excretion.

Cornwall does not wish to overstate her concerns. The really serious cases are rare. 

“If we look at the numbers, the regular health concerns dwarf marijuana,” she says. “Obesity is a much bigger problem, leading to other complications. Dogs get diabetes. Even if they get into THC . . .Yes, it’s an issue, but usually those animals are going to be okay.”

But not always. While Cornwall has never seen or heard about an animal dying of cannabis poisoning, the Canadian study reported that “10 veterinarians cited death as an outcome for 16 cases.”

Caveats again: “The details surrounding each case,” the researchers said, “were not captured.” Chocolate is a dangerous, sometimes lethal, toxin for dogs. What if the dog ate a pot brownie? Which substance would be to blame? Were there underlying conditions that compromised the dog’s health?

But “(i)n other cases,” the report continues, “it may be possible that cannabis . . . resulted in death directly, for example cases that report coma, uncontrolled seizures, or respiratory arrest …”

“Coma” and “uncontrolled seizures” sound a lot like Mookie. If that’s the case, he dodged a bullet.

A Surprising Theory

On that Monday morning in April, Ellen took Mookie out for a short walk before going to play pickleball and then delivering meals for the Montpelier Senior Center. She and Bob live on a hillside just above Berlin Pond. The road around the pond is great for walking. Mookie, being an exemplary golden retriever (this writer, by contrast, and gleefully, owns a hound), doesn’t need a leash.

“At the south end of the pond there’s an area where there are often fishermen,” Ellen explains. “Sometimes people congregate there late at night.”

Just past the fishing spot there are woods, and people are apt to go a little way into the woods for any number of reasons.

“There’s always stuff around,” says Ellen, “and Mookie likes to investigate. I’m pretty sure I saw him wolf something down.” They returned home and Ellen set off for her day. But Bob called her shortly after noon — Mookie’s lunchtime — to report that something was wrong.

“He couldn’t get up,” Bob recalls. “His back legs weren’t really moving. He was sort of dragging, and then he plopped down. He was pretty much comatose.”

Ellen raced home and they loaded Mookie into the car — with difficulty; he was 70 pounds of dead weight — and hightailed it to ORAH. The diagnosis came quickly: marijuana — THC poisoning.

“Because not only was he catatonic,” Ellen says. “He was also pissing himself. It turns out that those two symptoms are pretty classic when dogs ingest it.”

Alison Cornwall was not Mookie’s vet that day, but she confirms Ellen’s account.

“Over time, we’ve seen an increasing number of animals who have come in with characteristic signs of marijuana intoxication, which look very classic to us at this point,” she says. “They look depressed and very much not like themselves; often they will drip urine and not be able to walk straight. They’re just very … what’s the word? Soporific.”

Yet, legal or not, sometimes questioning the dog’s owner about what their pet may have discovered is a bit touchy.

“I try to preface this by letting them know, ‘I think this is marijuana intoxication. If that’s the case the treatment is pretty straightforward and I know what to do. If it’s not marijuana, then I really need to know what it is to know how to treat it. And figuring out what it is” — she pauses, and says, “Here’s the kicker! — ‘is very expensive.’”

There are multiple “tox screens” for multiple toxins, she noted, and a charge for each experiment.

“It comes down to a choice between, ‘We can do this without it being too expensive,’ versus ‘Okay, suddenly you need to plan for a $1,500 or $2,500 bill right now.’ Then a lot of times people will just say, ‘Actually, I do have some friends who come over and have it,’ or be even more open and say, ‘I have marijuana and my dog got into it.’”

“But,” she continues, “we have a lot of people who truly cannot figure out where the dog developed this. We have an in-house THC test, so if it’s positive we’re really proving, ‘Yeah, this is the cause.’”

Mookie’s people didn’t doubt the diagnosis and thought they knew where he had found it. More puzzling, though — and this seems often the largest unknown — was what, exactly, Mookie ate. 

People theorize that cannabis-stricken dogs get into compost that contains THC; conceivably, they find their owners’ nighttime gummies unprotected on the counter; in homes and backyards where marijuana products are part of people’s way of life, baked goods containing pot might be within Fido’s reach, or the marijuana butter people use in their recipes. Are roaches (butts) left around, and would they actually interest dogs? 

Ellen Drysdale has another theory. Exemplary though he may be, Mookie will indulge in the occasional turd. 

“He only eats frozen dog poop, but he’ll eat human poop in any form.” And alas, she says, partiers will occasionally relieve themselves in the woods near Berlin Pond.

Alison Cornwall, the ORAH veterinarian, had never thought of this, and as a scientist she sought to reason it through.

“Interestingly, the THC in the marijuana plant is not absorbed very well, and it takes a lot of fat — lipid — to be absorbed in the intestines. Which is why, when the local shops are selling edibles, they often have a very high fat content to increase absorption. And for people who are taking THC, if they took it with a high-fat meal [brownies, anyone?] they would absorb more of that medication or drug if they have a lot of fat in the intestines. 

“So it does make me wonder. I know it’s not well-absorbed, so does that mean that a fair amount of it is passed in the feces? I suspect that’s a reasonable thought, but it never occurred to me.”

The Canadian research paper does not provide Cornwall’s scientific analysis, but it confirms Ellen Drysdale’s theory.

“The products that often led to cannabis toxicosis,” it says, “were edibles and dried cannabis. Other products reported by veterinarians . . . were discarded joint butts, human feces, cannabis-infused butter/oil, and compost.”

And while dogs are by far the most often-reported victims of our carelessness with marijuana materials, other animals who live with us,  according to the Canadian study, can succumb. “Cases were also reported in cats, iguanas, ferrets, horses, and cockatoos.” 

Unanswerable at the moment (research, perhaps, will be undertaken) is whether wild animals are at risk. 

“I hadn’t thought about that,” says Cornwall, “but I’m sure they must be. There must be all sorts of raccoons out there having a really bad day.”

It’s On Us

Mookie’s days are just fine now, but it was a rough ride. At ORAH’s recommendation, his folks took him to BEVS for overnight attention that Monday.

“On Tuesday evening, after about 24 hours, BEVS told us ‘You might as well take him home,’” Ellen says. “But he was still almost a dead dog.”

Things got worrisome over the next couple of days as his lethargy continued. With all the fluids he’d been given intravenously his urine leakage — in the house — was constant. (“Smelly, too,” Ellen says.) The vets at Onion River, where they returned a time or two as his illness lingered, seemed concerned about his occasional convulsions.

“Thursday was the hardest day,” says Bob. “He was just staggering terribly, and the doctor at Onion River really seemed to think there had been neurological damage.” 

They wondered if the vet was trying to prepare them for a difficult decision. The vets also urged them to somehow get food into him. When he was relatively cognizant, Ellen hand-fed her boy bits of hamburger laced with bacon fat.

On Friday Mookie rallied. After five days he gradually returned to being Mookie.

Yet he’s Mookie in a world with a new and unexpected peril — caused, as peril often is, by human beings. A new toxin is spreading, in our homes, in our yards, in the wilderness. It’s on us now to prevent golden retrievers, raccoons, and cockatoos from having a very, very bad day.