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The state of veterinary medicine has advanced significantly in recent years and thanks to the availability of more effective medicine, many pets are living longer than they would have years ago. With age however, comes the onset of problems such as arthritis and other forms of pain and inflammation. Conventional pharmaceuticals commonly used to treat pain sometimes have a negative impact on the immune system, GI tract, liver, and kidneys. Additionally, they don’t always work as well as we would like them to – for humans as well as our pets.1

Of all the uses of cannabis in human and veterinary medicine, pain relief is perhaps the most well-documented. Research trials have shown profound pain-relieving effects from cannabis for a variety of medical conditions. Extracts of THC and CBD have been shown to provide relief in human patients with advanced cancer pain2 as well as in those with nerve-related pain.3

Studies evaluating the efficacy of cannabis in treating arthritis in dogs have been completed as well. A recent study from Cornell University showed reduction in pain scores in dogs with arthritis – with no negative side effects – when treated with CBD vs. placebo.4  In a more practical sense, many veterinarians and pet owners have seen the positive effects of medical cannabis for the treatment of arthritis and other forms of pain in animals. The research merely confirms what many of us have seen first-hand.

Forms of Cannabis Medicine for Pets

Medical cannabis for pets usually comes as a liquid oil or as treats. Liquids are preferable because the dosing can be accurately controlled and because CBD may be better absorbed through the tissues of the mouth rather than through the digestive tract. 

Vaporized or smoked cannabis should NEVER be used with pets. This can damage their lungs and can lead to accidental overdose.

Similarly, edibles for humans should not be given to your pet as they are impossible to dose accurately and they may contain ingredients (such as raisins, chocolate, etc.) that are toxic to animals.

How to Choose the Right Medicine

When considering cannabis as a medical option for the treatment of pain and inflammation, it is important to understand how the various components of a cannabis preparation may affect your pet. Some important factors to keep in mind are:5

  • The Entourage Effect: The synergistic benefit of whole-plant cannabis related to the quantity and distribution of major and minor cannabinoids, terpenes, and flavonoids. These factors affect the degree of biological activity and the spectrum of diseases treated.
  • The use of the appropriate ratio of THC and CBD as well as dosage are critical to success.
  • Consider other medications being given concurrently with respect to possible drug interactions.
  • Always consult with your veterinarian before beginning any new medication or supplement for your pet.

Ratios of THC to CBD frequently range from as high as 20:1, to even ratios (1:1), to 1:20.  The decision of which product or ratio to use for a pet with pain/inflammation often depends on the severity of the pain and its origin. The following is a guide to choosing ratios for treating pain and inflammation in animals.

High CBD or Hemp-Based CBD

  • 4:1 to 20:1 CBD-to-THC or, in the case of hemp, little to no THC
  • Mild to moderate pain such as arthritis and back pain

Even Ratio

  • 1:1 CBD to THC
  • Moderate pain such as arthritis and back pain

High THC Ratios

  • 4:1 to 20:1 THC-to-CBD
  • Severe pain such as cancer pain, nerve pain, and advanced arthritis

When using cannabis as medicine for pets, the first thing to remember is that any significant side effects are unacceptable. Getting your dog or cat stoned is never OK, even with medical cannabis. The goal with cannabis therapy in pets is to relieve the symptom being treated with no other side effects. Their normal patterns of behavior should be unaltered after receiving the therapy.

Dosage Guide for Pets in Pain

Following are guidelines for dosing THC and CBD in cats and dogs. Always consult with your veterinarian before beginning cannabis therapy for your pet.

THC Dosing

  • THC is always the limiting factor when dosing.
  • 0.2 – 0.6 mg THC per 10 pounds of body weight twice daily.
  • Start low and slowly increase the dose every 4-7 days.
  • Higher doses may be possible/necessary on a case-dependent basis.
  • Monitor closely for sedation, loss of balance, or loss of mental acuity.  Decrease the dose or discontinue immediately if any side effects are seen.

CBD Dosing

  • 0.5 – 5 mg CBD per 10 pounds of body weight twice daily.
  • Start low and slowly increase the dose every 4-7 days.
  • Frequently doses nearer the lower end of the range are effective.
  • Higher doses of CBD may be beneficial in certain circumstances.

Medical cannabis can be of great benefit to animals in pain. Ultimately, however, safe and effective use of cannabis requires an understanding of the milligram amounts of THC and CBD (or other cannabinoids), the ratio of cannabinoids, and availability of a medicine in a concentration appropriate for dosing a veterinary patient.

Nothing is more important than the safety of your pet, so don’t make guesses or assume anything about the content or dosing of cannabis medicines. 

Gary Richter, MS, DVM, CVA, CVC, GDWVHM, a Project CBD contributing writer, is an Oakland-based veterinarian. His articles focus on practical information for using cannabis to treat medical conditions in pets. © Copyright, Project CBD. May not be reprinted without permission.


  1. Veterinary-specific research into cannabis as medicine is in its earliest stages. Much of the foundation for the use of cannabis in animals is based on studies in laboratory models and in humans along with anecdotal evidence to support efficacy. While this may be a tempting leverage point for those who wish to stop or slow the use of cannabis in veterinary medicine, consider how many veterinary drugs and treatment protocols have their beginnings in laboratory models or human studies. There is no shortage of research data demonstrating the efficacy of cannabis for a host of disease conditions, including pain and inflammation.
  2. Johnson, J. R., Burnell-Nugent, M., Lossignol, D., Ganae-Motan, E. D., Potts, R., & Fallon, M. T. (2010). Multicenter, Double-Blind, Randomized, Placebo-Controlled, Parallel-Group Study of the Efficacy, Safety, and Tolerability of THC:CBD Extract and THC Extract in Patients with Intractable Cancer-Related Pain. Journal of Pain and Symptom Management,39(2), 167-179. doi:10.1016/j.jpainsymman.2009.06.008
  3. Weizman, L., Dayan, L., Brill, S., Nahman-Averbuch, H., Hendler, T., Jacob, G., & Sharon, H. (2018). Cannabis analgesia in chronic neuropathic pain is associated with altered brain connectivity. Neurology,91(14). doi:10.1212/wnl.0000000000006293
  4. Gamble, L., Boesch, J. M., Frye, C. W., Schwark, W. S., Mann, S., Wolfe, L., … Wakshlag, J. J. (2018). Pharmacokinetics, Safety, and Clinical Efficacy of Cannabidiol Treatment in Osteoarthritic Dogs. Frontiers in Veterinary Science,5. doi:10.3389/fvets.2018.00165
  5. Russo EB. Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects. British Journal of Pharmacology. 2011;163(7):1344-1364. doi:10.1111/j.1476-5381.2011.01238.x.

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