In early 2019, ASPCA Poison Control reported a 765% increase in calls related to marijuana ingestion over a 10-year period. The trend didn't slow down: by 2022, the center handled almost 11% more calls related to possible marijuana ingestion than the year before, and logged an increase of nearly 300% over the previous five years. Meanwhile, Pet Poison Helpline saw a 448% increase in marijuana-related cases over six years. In fact, recreational drugs made ASPCA's annual list of top pet toxins for the first time.

Dogs have far more cannabinoid CB1 receptors in the brain than humans do. Specifically, they have a much higher density of CB1 receptors in the cerebellum and brainstem — the areas that control coordination and vital functions — compared to humans, whose receptors are concentrated mostly in the hippocampus, the region responsible for learning and memory. This anatomical difference explains why the most common symptom in poisoned dogs is loss of coordination (ataxia), and why at high doses it can affect functions as basic as breathing or heart rate.

A total of 223 dogs with known marijuana ingestion or a positive THC result on a human urine multi-drug test were studied clinically. The average age was 1 year (range: 1 month to 12 years) — meaning puppies and young dogs, more curious and less averse to trying new things, are overrepresented. A telling detail about human behavior: most owners (68%) initially denied the possibility that their dog had been exposed — which delays diagnosis and complicates veterinary treatment.

A 2018 study found THC in the bloodstream of a cat that had been exposed to secondhand cannabis smoke. The cat developed alternating states of agitation and apathy, each lasting several minutes. Beyond direct smoke exposure, there's a second, less obvious route: when smoke settles on their fur, cats ingest those compounds while grooming (licking their fur), adding an exposure pathway many owners don't think about.

The probable lethal oral dose exceeds 3-9 grams of delta-9-THC-dominant plant material per kg of the dog's body weight. There is no published median lethal dose (LD50) data, and lethality is extremely rare. Research in dogs and monkeys showed that oral doses of delta-9-THC and delta-8-THC between 3,000 and 9,000 mg/kg were not lethal, and all animals recovered within 24 hours of ingestion. This means cannabis has a very wide safety margin compared to other common household toxins (like chocolate or human anti-inflammatories) — the real problem isn't so much the risk of death, but the animal's and owner's distress, and the risks associated with edibles containing other toxic ingredients.

Pets that have ingested edibles may also have potential exposure to other toxins present in the same product — such as chocolate, xylitol, or raisins — as well as the risk of ingesting foil wrapping or other packaging materials. In clinical practice, this matters as much as the THC itself: cannabis gummies coated in chocolate combine two distinct toxins, and xylitol (a common sweetener in "healthy" baking) is lethal to dogs at doses far lower than THC.

If ingestion was recent (within 1-2 hours), the vet may induce vomiting to clear the toxin from the system. However, this isn't always recommended, since it can sometimes worsen clinical signs — it's a decision that belongs exclusively to the vet, never to the owner at home.

Treatment is largely supportive, and includes medication to control vomiting and nausea, intravenous fluid therapy, temperature therapy (warming or cooling depending on the case, since hypothermia can occur), and general nursing care. Most dogs recover from marijuana intoxication within 24-72 hours with proper treatment, although severe cases — especially after ingesting large amounts of THC or if the animal has other health issues — can become life-threatening.

Cornell's veterinary school conducted a double-blind, placebo-controlled trial in dogs with osteoarthritis and multi-joint pain. Sixteen dogs received CBD oil made from industrial hemp or a placebo oil every twelve hours for four weeks, using a crossover design with a two-week washout period between phases.

The dose studied was 2 mg/kg of CBD every 12 hours. Veterinary evaluations showed a significant decrease in pain and an increase in activity after treatment with CBD oil, and both vets and owners reported no short-term side effects. More than 80% of dogs with osteoarthritis showed greater comfort and activity while taking CBD at that dose. The study was funded by ElleVet Sciences, a company that makes hemp products for pets with joint and muscle issues — a relevant detail when putting the results in context.

CBD is not approved as a food supplement or veterinary medicine in Spain, which means it is not legal to give it orally to pets as a regulated product — there are no authorized veterinary medicines containing cannabidiol. Topical (external) use is permitted, as long as the products contain less than 0.2% THC and are specifically labeled for cosmetic or external use.

If you use cannabis in a household with pets: avoid smoking in closed rooms where they're present, store cannabis and edibles in airtight containers out of their reach, improve ventilation in the spaces where you smoke, and contact a vet if you suspect any exposure, no matter how minimal it seems.

• Difficulty breathing or very slow breathing.
• Total loss of coordination, inability to stand, or coma.
• Very low body temperature (hypothermia) or intense tremors.
• Seizures.
• Abnormally slow or irregular heart rate.
• Suspicion that the edible also contained chocolate, xylitol, or raisins.
• Any symptom that gets worse instead of better after the first few hours.

When in doubt, it's better to call the vet and err on the side of caution than to wait and see if it improves on its own.

This article is for informational and harm-reduction purposes only, based on published veterinary literature. It does not replace evaluation by a veterinarian. If your pet has been exposed to cannabis in any form, contact your vet or an emergency veterinary clinic immediately — don't wait for symptoms to worsen. Nothing in this article should be interpreted as a recommendation to administer THC or CBD to a pet without veterinary supervision.