I am writing this on what has become a popular (unofficial) holiday here in Colorado – 4/20 – a day that celebrates marijuana and everything associated with it. I thought I’d take the opportunity to talk about what we’ve learned about pot and pets in a state where marijuana has been legalized for both medical and recreational use.


Pets can be exposed to pot in three ways.


1. Accidental Exposure


Most pet exposures to pot occur accidentally. Leave pot brownies or other “edibles” where dogs can get to them and chances are they’re going to eat them. Accidental exposures in cats are far less frequent due to their more discriminating palates.


A study published in 2012 looked at marijuana toxicity in 125 dogs after Colorado legalized medicinal use of the drug. The researchers found a 400% increase in the number of dogs being brought into Wheatridge Veterinary Specialists in Denver and Colorado State University Veterinary Teaching Hospital in Fort Collins after legalization. The symptoms of marijuana exposure in these dogs included:

  • difficulty walking (e.g., stumbling)
  • altered mental state
  • dilated pupils
  • urinary incontinence
  • increased sensitivity to stimuli
  • muscle twitches/tremors
  • vomiting


Two dogs died after eating baked goods made with medical grade tetrahydrocannabinol (THC) butter. They choked on their own vomit.


Anecdotally, veterinarians have seen another big increase in patients exposed to marijuana since recreational pot shops opened at the beginning of 2014. For example, a veterinarian in Fort Collins says, on average, she now sees one dog brought in for marijuana exposure every time she covers a night shift at one of the emergency hospitals here in town. Fort Collins isn’t that big; it has a population of around 155,000.


2. Intentional, “Recreational” Exposure


Unfortunately, many pet owners also intentionally try to get their pets high. Whether this is for the owner’s amusement or due to a misguided sense that the animal will enjoy the experience, giving a pet marijuana for “fun” is detestable. Do you know what your dog’s tolerance for THC is? Just look at that list of symptoms above.  Doing that to an animal who has no idea why they feel the way they do is simply cruel.


3. Medicinal Use


Some owners have also started giving medical marijuana to treat a variety of ailments in their pets. Most frequently pot is used to relieve pain and stimulate the appetite, often as a part of cancer treatment or for chronic disorders like osteoarthritis, but it is also sometimes used to reduce anxiety, nausea, or seizures. Most owners resort to medical marijuana when conventional treatments are no longer effective and many report obvious improvements in their pet’s quality of life.


But here is where things get tricky. I always recommend that owners consult with a veterinarian before giving their pet any new medicine. However, it is illegal for veterinarians to prescribe or even recommend treating an animal with marijuana. You might be able to find a vet who is willing to talk to you in general terms about how marijuana has been used in pets, but if we say much more than that, we could get into a whole heap of trouble… and on that note, I think I’d better sign off.



Dr. Jennifer Coates





Evaluation of trends in marijuana toxicosis in dogs living in a state with legalized medical marijuana: 125 dogs (2005-2010). Meola SD, Tearney CC, Haas SA, Hackett TB, Mazzaferro EM. J Vet Emerg Crit Care (San Antonio). 2012 Dec;22(6):690-6. 



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