THC (Marijuana) Poisoning in Dogs

Medically Reviewed by Amy Flowers, DVM on June 08, 2024
5 min read

If you smoke, vape, or eat marijuana, the “high” you feel from it may wear off in a couple hours. But if your dog is exposed to pot, it’s a different story. Marijuana is a known toxin for dogs. Even a small amount can cause a bad reaction and lead to marijuana toxicosis. That’s because your pooch’s body breaks down THC, the main psychoactive ingredient in weed, differently than yours does.

As more U.S. states legalize marijuana for recreational or medicinal use, the number of dogs with marijuana poisoning has jumped, too. In fact, in 2022, the ASPCA’s Animal Poison Control Center reported an 11% rise in calls about pets that were exposed to pot-related items than the previous year and an overall increase of 300% in the previous five years.

While marijuana rarely causes death in dogs, it may lead to serious symptoms. If you think your dog has been exposed to it, get medical attention immediately.

Your dog may have THC poisoning if they:

  • Stumble and cross over their feet as if they are “drunk”
  • Look dull and lethargic, but startle to catch their balance if they start to fall over
  • Have dilated pupils
  • Pee uncontrollably
  • Vomit
  • Have tremors and shake
  • Are agitated
  • Are very sensitive to sound and touch
  • Have an unusually low or unusually high heart rate

In some cases, if the reaction is very bad, your dog could go into a coma.

It usually takes 30-60 minutes after your dog eats marijuana for the effects to kick in. It may happen sooner if they inhale it. The timing can vary depending on a number of things, such as:

  • The dosage
  • Your dog’s size and age
  • How your dog was exposed to it
  • Other medical issues your dog might have

The high and other effects usually last 18-24 hours in dogs. Because THC is so toxic for dogs, they can’t just “sleep it off.” If you notice these symptoms, call your vet immediately.

Just like humans, dogs have cannabinoid receptors in their brains that process chemicals like THC. But even the smallest exposure to it is toxic for your pet. This is because your dog’s body can recycle cannabinoids.

When your dog is exposed to THC, the gut absorbs it and stores it in bile – a fluid made by the liver. When your pup eats its next meal, the THC-loaded bile is secreted into the intestines. This re-exposes them. This is why your dog’s symptoms are much worse.

Dogs can be exposed in a number of ways. They can:

  • Inhale secondhand smoke
  • Swallow parts of the cannabis plant (buds, leaves, or stems)
  • Eat marijuana-infused edibles and baked goods like brownies or cookies
  • Lick or eat THC oil or butter
  • Eat poop after someone has digested marijuana

The effects of the poisoning may be worse if your dog is exposed to marijuana along with other known toxins such as chocolate, raisins, the artificial sweetener xylitol, or high-fat foods.

THC is different from CBD (cannabidiol). CBD is a natural chemical compound found in cannabis or hemp plants and doesn’t contain any THC. So it doesn’t cause a “high.” In recent years, CBD oil has gained popularity and many people use it to treat various medical issues in dogs, like pain, anxiety, and seizures.

But there’s no scientific data to support its use and benefits in the long term. And CBD oil’s manufacturing and distribution isn’t well-regulated. So certain CBD products may contain small amounts of THC. This could be dangerous. Check with your vet to see whether CBD oil is right for your dog, and to make sure you have the right kind. But also know that in many states, vets legally can’t even talk to you about CBD oil. Laws are changing, so again, you’ll have to check.

There’s no specific test to check for marijuana poisoning in dogs. If you think your dog has been exposed to weed, your vet may:

  • Take a detailed medical history
  • Do a physical exam
  • Test stomach contents and urine for THC
  • Order an X-ray to check for marijuana packaging like foil, vape pen, or pipes

They may also order additional tests to rule out possible intoxication from alcohol, opiates, tranquilizers, and pesticides, among other known toxins.

Treatment options may vary depending on the how bad the symptoms are. If the vet sees your dog less than 30 minutes after the pot was eaten, it may be possible to induce vomiting. After 30 minutes, it becomes too hard and risky.

If the reaction is severe, your dog may need to be hospitalized.

If this is the case, treatments may include:

  • Drugs to stop vomiting and nausea
  • Drugs for agitation, tremors, or seizures
  • Intravenous (IV) fluids given through a catheter
  • Activated charcoal to reduce the amount of THC absorbed
  • Temperature therapy, involving warming or cooling

In some serious cases, your vet may also give intralipid therapy. It’s a type of IV solution that absorbs THC from the bloodstream.

For the best results, tell your vet the whole truth and don’t hide anything. Your vet’s main concern is your dog’s well-being, and they aren’t obligated to report anything to the police. If you have the THC product your dog may have been exposed to, take it along when you go to the vet. This can help your vet skip unnecessary tests or treatments.

The outlook is good, if your dog gets help soon after they are exposed. With proper and timely treatment, most dogs recover fully in 1-2 days. In more serious cases, it may take 3 days or more.

But the recovery may be longer if your dog is exposed to synthetic marijuana (“Spice,” “K2”), also known as “fake weed,” as the effects are worse.

Besides dogs, THC is also toxic for cats and horses, among other animals. But marijuana poisoning is more common among dogs, especially those that counter surf and explore anything in reach.

The best way to prevent THC poisoning in animals is to keep it out of reach so they can’t get into it by accident. Keep them away from areas where you may use marijuana.

If you suspect marijuana exposure, call the Animal Poison Control Center at (888) 426-4435 or head to your local vet’s office for help.