Marijuana Toxicity in Dogs


Last fall I moved to Portland, Oregon, where marijuana is legal. Though I do not use marijuana, I have become very vigilant to ensure my dogs don’t ever get exposed to it. Marijuana toxicity in dogs is a concern that has been heightened for me after seeing several friends’ dogs require emergency medical treatment for exposure over the last few months. With more communities across the country legalizing marijuana, your dogs may be exposed even if you personally don’t partake, and it’s important to know what to do.

Dr. Tina Wismer, DVM, MS, DABVT, DABT, is the Medical Director of the ASPCA Animal Poison Control Center. She explains that dogs do not respond well to tetrahydrocannabinol – THC – which is the chemical responsible for most of marijuana’s psychological impact.

Dr. Wismer cautions that, “Since [dogs] have a smaller body size and no sense of portion control, a dog can ingest a very large dose of marijuana all at once.” This risk is exacerbated by the prevalence of cannabis-infused food products in marijuana-friendly communities.

Symptoms of Marijuana Toxicity in Dogs

The symptoms of marijuana toxicity will vary based on the dog, but general symptoms in dogs include depression, vomiting, urinary incontinence, ataxia (wobbliness), tremors, stupor, and bradycardia (slow heart rate). However, Dr. Wismer explains about 25% of dogs exposed to cannabis will become stimulated instead of depressed and show agitation and high heart rate. Dogs with severe marijuana toxicity can develop low blood pressure and coma.

How Much Marijuana Will Make A Dog Sick?

Dr. Wismer advises that the size of your dog and the form of marijuana ingested determine how sick they will get. She cautions that cannabis concentrates such as those used in “edibles” are much more concerning than plant material when it comes to dogs, especially if chocolate is involved.

Precautions for Possible Marijuana Exposure

If you live in an area where marijuana is legal, and/or if you or someone in your household chooses to partake in recreational or medicinal use, Dr. Wismer advises the best way to protect your dog from a serious emergency is to, “make sure any product containing marijuana is out of paws’ reach at all times. Products in the form of an edible are especially dangerous as they often contain sugar and chocolate, which is also poisonous to pets.”

cannabis thc oil
iStock / Getty Images Plus/ NataGolubnycha

Dr. Wismer advises that dog guardians should treat marijuana just like any other drug or chemical – something that always stays out of their reach.

Talk about the dangers of marijuana and dogs to any house guests that might stay at your home. Ensure that dog walkers are aware of the risks. And as always, be vigilant about what your dogs are picking up on walks or at parks, as those are situations in which they could encounter discarded joints or other substances.

What to Do if Your Dog Consumes Marijuana

“If you suspect that your pet has ingested marijuana, call your veterinarian immediately,” says Dr. Wismer. She also suggests calling the Animal Poison Control Center (APCC) at (888) 426-4435. You will be asked to describe your dog’s symptoms, how much marijuana they ingested (if you know) and your dog’s size and weight to determine if immediate treatment is necessary.

Treating Dogs for Marijuana Toxicity

“If a dog hasn’t consumed a lot, the general treatment is to provide supportive care, including IV fluids to keep them hydrated and help flush the drug out of their system,” Dr. Wismer explains.

In severe cases of marijuana toxicity, veterinarians will provide lipid therapy through an IV. “Fat molecules bind with the THC in the pet’s bloodstream, allowing the body to shed a large quantity of the chemical faster,” says Dr. Wismer.

Most dogs who have been exposed to marijuana will recover with supportive care, though Dr. Wismer cautions there have been a few reported deaths in dogs who ingested concentrated marijuana products.

cannabis candies
iStock / Getty Images Plus/ Gwengoat

CBD for Dogs: Isn’t That Weed Too?

Dog treats and supplements containing CBD, or cannabidiol, are becoming increasingly common. Though CBD and THC are both derived from cannabis, CBD does not have any of the mind-altering properties that THC does.

Caroline Coile, PhD, is a writer and canine researcher who penned the book, Cannabis and CBD Science for Dogs. She has not heard of any reported cases of dogs overdosing with CBD products. She explains that CBD is most commonly used with dogs to treat anxiety, arthritis, inflammation and seizures, but has many other potential uses such as for autoimmune disorders, bone fractures, cancer, colitis, nausea and diabetes.

Coile emphasizes how dog owners should not confuse CBD with marijuana (which generally contains both THC and CBD, among many other chemicals), and that CBD does not get a dog high. She also states that CBD is, “probably the biggest breakthrough in a new class of drugs we’ve have in decades.”

On the other hand, Dr. Wismer says, “CBD products should not contain any mind-altering substances. However, we have seen dogs develop the same signs as THC ingestion after ingesting CBD-only products. As these products are not regulated, it could possibly be a quality control issue.”

Regarding the quality control of cannabis products, Dr. Wismer went on to explain that, “In one study looking at human products, 75 products were evaluated to determine the amount of cannabidiol and THC they contained. The results indicated that only 17% of products were accurately labeled, 23% were under-labeled and 60% were over-labeled with respect to THC content.”

If you are going to use CBD products with your dog, a lot of the research will fall to you and your vet to find companies and products that you feel comfortable with.

Unfortunately, there remain some unknowns. “This is certainly an area where more studies are needed to determine what the correct dose of CBD is for certain medical indications (anxiety, pain, etc.),” advises Dr. Wismer.

Sassafras Lowreyis an award-winning author and Certified Trick Dog Instructor. Sassafras’ forthcoming books include Tricks IN THE CITY: For Daring Dogs and the Humans That Love Them, Healing/Heelingand Bedtime Stories for Rescue Dogs: William To The Rescue.


  1. Very interesting. I’m a little confused though, what about dogs that like marijuana? For example, my old friend’s mom would smoke and her dog would be very excited to join her. He smoked with her for years and never had a health problem, he passed away at an old age.

    Does it only effect some dogs?