Cannabis Toxicity in Dogs

Published Dec. 13, 2022

What Is Cannabis (Marijuana) Toxicity in Dogs?

For centuries the cannabis or marijuana plant has been used for medical purposes, and hemp, which is another variety of the plant, has been used for manufacturing products such as rope, textile, and paper. Today, recreational use of cannabis is legal in many states, increasing its availability in homes and exposure to pets, particularly dogs.

People consume marijuana in different ways. What they are actually ingesting comes from the dried flowers and tops of the Cannabis sativa plant that contain psychoactive substances. Cannabis toxicity occurs when your dog ingests the plant itself, eats products containing cannabis, or inhales the secondhand smoke or vapor from a marijuana cigarette or vaporizer.

With wider public use of marijuana, the Pet Poison Helpline (855-764-7661) has seen a 400% increase in the past six years in calls related to marijuana toxicity in pets.

Why Is Cannabis Toxic to Dogs?

The marijuana plant contains more than 100 chemicals called cannabinoids. Tetrahydrocannabinol, or THC, is the principal and most active ingredient in cannabis; it causes a high and is responsible for toxicity in dogs.

The exact amount of each cannabinoid varies widely from strain to strain and plant to plant. A small amount of cannabis is all it takes to cause toxicity in dogs. When cannabis gets into the bloodstream of dogs, it travels to the brain where receptors trap the chemicals and alter the brain’s chemical messengers such as dopamine and serotonin.

Cannabinoid receptors are located in specific areas of the brain associated with memory, pleasure, thinking, coordination, and sensory functions. Compared to humans, dogs have more cannabinoid receptors in their brains, making the effects of cannabis more dramatic and potentially more toxic.

Common Types of Cannabis

Common types of cannabis that dogs may be exposed to include:

  • Fresh, growing plant

  • Dried plant material used for smoking

  • Vaporizer or electronic cigarette devices

  • Edibles such as brownies, butter, and gummies

  • Herbal tea or other beverages

  • Capsules or other preparations compounded as medication

Marijuana-infused edibles often contain higher concentrations of THC than the plant material (buds, leaves, and stems) and pose a greater risk for poisoning in pets.

Symptoms of Cannabis Toxicity in Dogs

Signs of cannabis toxicity in dogs occur 5 minutes to 12 hours after exposure and can last from minutes to days. Symptoms are visible 30 minutes to 1 hour after ingestion of the drug, or sooner if inhaled.

Common clinical signs of marijuana toxicity in dogs include:

Other, less common, clinical signs of marijuana toxicity in dogs due to exposure to high concentrations include:

  • Vocalization, including whining and crying

  • Agitation, aggression

  • Trouble regulating body temperature

  • Incontinence, urine dribbling

  • Slow or fast heart rate

  • Altered blood pressure

  • Slow breathing rate

  • Tremors

  • Seizures

  • Coma

My Dog Ingested Marijuana. Now What?

If you suspect that your dog has ingested marijuana or is displaying signs of toxicity after inhaling it, contact a veterinarian immediately.

Your veterinarian may conduct a urine test to detect THC and confirm the diagnosis. Informing your veterinarian what your dog was exposed to or has ingested is important to guiding the course of treatment. For example, when your dog eats a brownie made with THC butter, it requires a different treatment than when they inhale a THC product. Eating the brownie requires treatment for cannabis and chocolate toxicity, whereas inhalation may require additional treatment for respiratory irritation.

You and your veterinarian may need to call the Pet Poison Helpline for advice on the next steps in treating your dog’s cannabis toxicity. Veterinarians do not recommend inducing vomiting at home due to the risk of ulceration to the esophagus and aspiration pneumonia, which is a life-threatening situation that occurs when dogs accidentally inhale their vomit.

Treatment of Cannabis Toxicity in Dogs

Your veterinarian will do a physical and neurological exam and perform basic blood and urine testing to assess your dog’s level of cannabis toxicity.

Depending on the severity of toxicity and how it occurred, your veterinarian will provide supportive care to improve your dog’s symptoms. There is no antidote or reversal for marijuana poisoning. Your dog may be treated as an outpatient but may need to stay overnight in the hospital for observation.

Your veterinarian may use a warming device to stabilize body temperature, administer anti-nausea medication, and give IV fluids to support blood pressure and treat dehydration. The vet may also induce vomiting at the hospital to prevent further toxin absorption if it was a recent ingestion.

Medications may be given to decrease anxiety and restlessness. It may be recommended that your dog be temporarily kept in a dark, quiet area of your home to help prevent sensory overstimulation, which may worsen symptoms. To prevent self-harm due to behavioral changes, your dog may also be confined in a safe space.

In life-threatening cases, your dog’s stomach may be pumped. Activated charcoal may be given every 6 to 8 hours to neutralize the toxin. Enemas are also used to reduce toxin absorption from the gastrointestinal tract.

If cannabis is ingested along with toxic or problematic substances such as xylitol, chocolate, raisins, or foods containing a lot of fat, supportive care or additional treatments may be required.

Recovery of Cannabis Toxicity in Dogs

Toxicity in dogs is rarely fatal when cannabis is ingested or inhaled alone. Fatalities are more common when cannabis is eaten with other substances such as xylitol, chocolate, or raisins.

Because THC is stored in fat cells, the effects of ingestion can last for several days. With proper treatment, dogs usually recover fully within 24 to 36 hours, but some cases may take up to 72 hours. The recovery time depends on the type of cannabis and if the dose was ingested or inhaled.

How To Keep Dogs Safe From Cannabis Toxicity at Home

Remember that edibles with THC may be particularly tempting for your dog. To keep pups safe and prevent cannabis toxicity at home, avoid leaving marijuana edibles in plain sight and keep them out of your dog’s reach in closed, elevated cabinets or in a locked drawer.

If marijuana is being smoked or vaped, keep your dog in a separate area with good ventilation until the smoke or vapor has cleared.

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  1. Stillabower A. Pet Poison Helpline. Marijuana Toxicity in Pets.

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Barri J. Morrison, DVM


Barri J. Morrison, DVM


Barri Morrison was born and raised and currently resides in Ft. Lauderdale, Florida. She went to University of Florida for her...

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