How Much Do We Know About Medical Marijuana for Pets?

Published Aug. 3, 2015

The Colorado Board of Health recently voted against adding post-traumatic stress disorder (PTSD) to the list of conditions eligible for treatment with medical marijuana. According to the Denver Post, “Currently allowed uses of marijuana include pain (93 percent of recommendations), cancer, epilepsy, glaucoma, muscles spasms, multiple sclerosis, severe nausea and wasting disease (cachexia).” Members of the Board of Health cited a lack of scientific evidence for marijuana’s effectiveness in treating PTSD as the primary reason for their decision.

But a lack of scientific evidence doesn’t seem to be stopping pet owners from giving medicinal pot to their pets. If you do a quick Google search for “medical marijuana” and “pets” you’ll find lots of stories about owners who have given marijuana to their often chronically ill/dying pets. Anecdotally, they’ve seen some fairly remarkable improvements in their pets' quality of life, at least in the short term.

Owners are most often hoping that pot will help relieve their pet’s pain and/or work as an appetite stimulant. Marijuana has also been used in the treatment of anxiety, nausea, and seizures, primarily in dogs. But here’s the rub: even in the pot-friendly state of Colorado, medical marijuana is only legal when a physician recommends it for a human patient. Veterinarians cannot prescribe marijuana for pets.

Recreational marijuana is widely available, but I worry when I hear of owners giving it to their sick pets. Today’s varieties have a much higher percentage of tetrahydrocannabinol (THC) and are therefore MUCH stronger than what used to be available a few decades back. In fact, a friend’s dog recently suffered through what could only be described as a “bad trip” after ingesting a tiny amount of marijuana off the sidewalk in their neighborhood. The dog recovered, but the outcome could have been different if he was already critically ill.

Another option that is available to interested owners is cannabidiol (CBD), which is derived from hemp plants (hemp is basically marijuana that doesn’t make much THC). CBD has recently garnered a lot of attention duet to its apparent ability to control seizure activity in people. According to a paper that explored its potential usefulness in human medicine, CBD “displays a plethora of actions including anticonvulsive, sedative, hypnotic, antipsychotic, antiinflammatory and neuroprotective properties.”

Unfortunately, research into the potential usefulness of CBD in pets is lacking. The only studies I have seen found that CBD is very poorly absorbed after oral administration in dogs. “In three of the six dogs studied, CBD could not be detected in the plasma after oral administration. In the other three, the oral bioavailability ranged from 13 to 19%.”

So, while CBD is available to pet owners (some companies are even making CBD dog treats!), it’s hard for me to recommend its use. I doubt CBD supplements are dangerous, however. I suspect the biggest risk is to your wallet.

Have you treated a sick pet with marijuana or CBD? What’s your experience?

Dr. Jennifer Coates


Cannabidiol in medicine: a review of its therapeutic potential in CNS disorders. Scuderi C, Filippis DD, Iuvone T, Blasio A, Steardo A, Esposito G. Phytother Res. 2009 May;23(5):597-602. 

Pharmacokinetics of cannabidiol in dogs. Samara E, Bialer M, Mechoulam R. Drug Metab Dispos. 1988 May-Jun;16(3):469-72.

Image: Sherry Yates Young / Shutterstock

Jennifer Coates, DVM


Jennifer Coates, DVM


Dr. Jennifer Coates is an accomplished veterinarian, writer, editor, and consultant with years of experience in the fields of veterinary...

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