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Marijuana Toxicity

August 21, 2019

Despite being illegal in Minnesota, recreational marijuana use is on the rise as legislation changes around the country. In addition, medicinal use is legal, though regulated. Therefore, we are seeing more pets with marijuana toxicity than we used to. Even if you don’t personally use, people are not always aware what others in their households may be doing, so it is important for us all to recognize the signs of toxicity. So let’s get started!

Dogs and cats are most commonly exposed to marijuana by eating it: Getting into medication, a stash, edibles, or garbage with discarded/used buds or leaves. We have even seen toxicity from a dog licking carpet where plant material was spilled. Occasionally, second-hand smoke or blowing smoke into a pet’s face can result in toxicity; this is more of a problem for cats and small dogs.

Like humans, the active compounds in marijuana affect the central nervous system. In dogs, symptoms include: Dilated pupils, low heart rate, lethargy, sedation, incoordination and balance issues, low body temperature, tremors/twitching/shivering, hypervigilance/easily startled (probably a similar experience to paranoia in humans), disorientation, urinary incontinence/uncontrolled urination, vomiting, hyperesthesia (extreme sensitivity to touch), excessive drooling, and vocalization (howling, whining). The “textbook” case is a dog who is sleepy, easily startled, dribbling urine, and trembling/shivering.

Clinical signs in cats include periods of inactivity alternating with periods of restless activity, pacing or aimless wandering, spontaneous jumping, head bobbing or weaving, swaying while walking, incoordination or balance issues, increased or decreased body temperature, increased meowing, spontaneous hissing, dilated pupils, excessive drooling, spontaneous aggression, difficulty swallowing, or ravenous hunger alternating with refusing to eat anything.


In the vast majority of cases, marijuana toxicity is not fatal. However, when exposed to high amounts, unusually potent products, or adulterated/contaminated products, more serious signs such as extreme agitation, hyperactivity, dangerously high body temperature, abnormal heart rhythms, seizures, and death may occur.

Diagnosis is made primarily by clinical signs and a history of known or possible exposure. Over the counter human urine tests are not reliable in pets, and laboratory tests that are reliable have a long turnaround time. It is therefore extremely important to be honest with us if you think your pet may have gotten into marijuana; our doctor/patient relationship with your pet affords certain legal protections and our primary concern is your pet’s health. We are not going to report you to any legal agency! Also, not knowing that exposure is a possibility means that extensive diagnostics may be recommended to rule out other, more serious neurologic diseases.

Treatment depends on the severity of symptoms and which symptoms are present. Because there is no antidote to marijuana itself, individual symptoms are treated as needed until the drug is out of the system. In mild cases this may simply be supportive care such as IV fluids and drugs to calm agitated pets in a quiet, low-stimulation environment. In more severe cases it may also include drugs to regulate heart rate and blood pressure, control seizures, control vomiting, control derangements in body temperature, and so on.

This is definitely one case where prevention is the best medicine. Our pets cannot consent to or understand the idea of being high for recreational purposes and usually appear quite distressed by the experience, so please keep any products out of your pet’s reach and don’t intentionally give them marijuana, including blowing smoke in their faces. We want to keep your pets happy and healthy!

Karen Christopherson, DVM CVA


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