Medical Cannabis and Its Impact on Pets

medical marijuana and pets Many veterinary clients wonder about the benefits of medical marijuana for pets since the legalization of the drug for humans in Massachusetts.  Currently, veterinarians are bound by federal law and can lose their Drug Enforcement Agency (DEA) license if we prescribe cannabis for pets. This is because the use of it is illegal at the federal level in the United States.

Unfortunately, veterinarians have a lot of experience with dogs getting into human cannabis supplies. These dogs have signs of toxicity such as drowsiness, incontinence and nervous symptom signs including seizures or death.  Sometimes they have anxiety and hyperactivity if there is something else mixed in. It could be a pesticide but we just don’t know.  We treat a lot of these dogs and our team has come to recognize the signs quite easily.

According to discussions on, the Veterinary Information Network, the great majority of veterinarians will not risk losing their federal Drug Enforcement Agency prescribing license by prescribing any type of cannabis or hemp to a pet.

Usually, veterinarians are used to dealing with drugs that are widely tested on animals before coming to the veterinary market. Cannabis is unique in that it is in wide use by humans before being tested for safety in animals. Veterinarians have very little evidence about the effect of cannabis or hemp in animals.

The following are the effects of cannabis on humans:

According to a British review published in 2013, CBD (cannabidiol- the non-psychoactive inducing chemical in hemp and marijuana) has the following benefits.

Antiemetic (motion sickness – Reduces nausea and vomiting
Anticonvulsant – Suppresses seizure activity
Antipsychotic – Combats psychosis disorders
Anti-inflammatory – Combats inflammatory disorders
Antioxidant – Combats neurodegenerative disorders
Anti-tumoral/Anti-cancer – Combats tumor and cancer cells
Anxiolytic/Anti-depressant – Combats anxiety and depression disorders.

My concern is that pet owners will read about these benefits in humans and self-prescribe a cannabis or hemp product for their pet. We already have a few clients who are doing so with pets that have unknown incurable inflammatory diseases. My big concern with owner experimentation is that we have no research to show that pets have been helped with cannabis.

Sadly, owners treating with marijuana may hurt pets. Veterinary Immunologist, Dr. Jean Dodds raises the point that we have to be aware that the amount and type of approved pesticides and fungicides used on plants vary by state for human consumption. California passed the medical use of marijuana in 1996.  She states that currently, 21 years later, the state of California does not regulate any pesticides, fungicides, chemicals, foreign material, heavy metals, or microbiological impurities (mold, bacteria) in cannabis. Regulation of pesticide use will start in 2018 in California. Massachusetts is far behind California on cannabis regulations.

According to Dr. Dodds, “‘One investigative report found that 41 out of 44 samples tested contained 16 pesticides at levels so high that the marijuana probably would have been banned in states with these regulations.” None of these state regulations addresses the toxicity or safety of these contaminants in pets

Research must be done to answer the many questions about marijuana for use in pets.  One of the big hurdles to getting the research done is that marijuana is listed as a Schedule 1 drug by the DEA. This puts it on the same schedule with heroin and other dangerous drugs.  Because the DEA designated such a strict Schedule it is much harder for researchers to run experiments on marijuana and test its animals.

According to the American Veterinary Medical Association Numerous physician and healthcare organizations, including the American Medical Association, American Public Health Association, and National Association for Public Health Policy, are urging the federal government to reschedule marijuana so that research can be initiated.

Once the research has been done and the regulations are in place to protect pets from pesticide, mold or heavy metal contamination we can start to consider prescribing only if it is legal at the federal level. Currently, my advice is to keep all forms of marijuana out of reach of pets at all times.

Your neighborhood vet,

Dr. Liz Bradt