“As marijuana is being legalized in more states and its use is becoming more widespread where it’s not legal, we’re seeing more intoxications,” says MedVet Columbus criticalist Natashia Evans, BVSc, DACVECC. “When users compound the drug with a fatty solution like oil or butter, two things happen. The toxicity increases and the risk of pets getting into it increases too.” Evans says that a dog that has ingested a comparatively small amount of the compounded drug can suffer dramatically more effect than if the animal ingests something like a “pot brownie.”

“Dogs may come in with severe pancreatitis, abdominal pain, and often near comatose,” Evans says. “Dogs often present with excessive and uncontrollable urination. They can often be confused with antifreeze or ethylene glycol toxicity.” She adds, “We get probably fifty percent admission by owners that the dog has ingested the drug; but we’ve seen enough of it that we typically can make a pretty confident diagnosis just from presentation.”

Clinical Signs of Marijuana Toxicity

Although a pet could show signs of marijuana toxicity post-inhalation, most cases are due to suspected or known oral ingestion. Marijuana toxicity can be seen in multiple species, dogs are by far the most common presentations to our hospitals with cats and other species representing a very small percentage of patients.

Patients may present with a range of clinical signs. Most commonly noted are lethargy, behavioral changes, urinary incontinence, and neurologic signs. On physical exam, unusual responses to stimuli and reddened or engorged conjunctiva may be noted. Severely affected pets can be comatose or die from their exposures. Severe cases of marijuana toxicity require hospitalization and treatment for hypotension, vomiting, anorexia and/or diarrhea.

The time from ingestion to onset of signs can be rapid (within minutes to hours). Because the offending ingredients in marijuana are stored in body fat, signs can persist for hours to days.

Marijuana Toxicity FAQ’s 

Can patients experience toxicity from inhalation and ingestion?

Technically yes, but the majority of toxicities are from ingestion.

Can cats experience toxicity?

Cats can experience toxicity but are a small percentage of all presentations. Dogs are most likely to experience toxicity.

How soon will patients show signs of toxicity and how long will they last?

Signs of marijuana toxicity can occur within minutes to hours after ingestion and can last for hours to days.

What other conditions can mimic the signs of marijuana ingestion?

The signs of marijuana toxicity are similar to several other toxic ingestions. Such toxins include other drugs such as OTC stimulants, chocolate, antidepressants, antiparasitics (amitraz), heartworm medications (ivermectin), rodenticides (bromethalin), antifreeze (ethylene glycol) and ethanol (rotting fruit, bread dough).

If you suspect your pet has ingested marijuana, call your family veterinarian or your closest MedVet.