Struck with severe arthritis, Topper, a 7-year-old Ibizan Hound, was in such pain he could hardly walk. He had to be carried outside to eat or use the bathroom, and medication wasn’t working. On a friend’s recommendation, his owner, Christy Moore, of Florence, Arizona, gave him cannabidiol (CBD). “Within three days, he could walk on all four legs and I was crying tears of joy,” she recalls. “It was the miracle we needed.”

Topper is among the thousands of furry family members that have found relief with CBD, one of 113 cannabinoids found in cannabis (hemp) plants. Success stories abound of how CBD has helped dogs overcome anxiety, reduce seizures and even beat cancer. 

Cannabinoids, including CBD and the psychoactive compound THC, are substances that mimic the naturally occurring chemicals produced in all vertebrates. Receptors for these endocannabinoids are found throughout the body, especially in the brain, nervous system and immune system, as well as the heart, lungs, liver, spleen, intestinal tract, muscles, bones and both the reproductive and circulatory systems. They act as master regulators that signal other systems when to speed up or slow down, working to stabilize the body and return it to homeostasis. Cannabinoids from the cannabis plant affect these same receptors, each in slightly different ways.

Unlike THC, which is toxic for dogs at prescribed human dosages, the most significant, documented side effects of CBD are diarrhea and changes in some liver enzyme values after several weeks. The main concern with CBD is that it inhibits cytochrome P450, a chemical in the body responsible for metabolizing most drugs. That means CBD could affect the effective potency of a prescribed drug. 

What Research Shows

While thousands of reports on CBD’s effect on laboratory animals and humans have been published, only a few have been conducted with dogs or cats. Still, CBD seems promising for arthritis, anxiety, itchiness and possibly seizures, cancer and other maladies.

Arthritis: In a Cornell University study, some dogs were initially so decrepit that their owners considered euthanasia, but after just days on CBD they were trotting around and even climbing stairs. A Baylor University study found similar improvement.

Itchiness: An Australian study found CBD reduced itchiness, inflammation and skin lesions by 51 percent after eight weeks of treatment. An American study also found CBD significantly reduced reports of itchiness.

Cancer: Cannabinoids are reported to induce cancer cell death and prevent metastasis. A Cornell University study found that CBD along with a standard chemotherapy drug reduced cancer cell proliferation in vitro more than the chemotherapy drug alone. Anecdotal reports from veterinarians have claimed CBD shrunk cancer cells or put dogs into remission.

Behavior: No controlled study has shown CBD to be more effective than prescription medications in reducing anxiety. A University of Kentucky study found physiological measurements of anxiety in response to noise were not significantly different for CBD versus a placebo, and were worse compared to trazodone (a drug commonly prescribed for anxiety). A University of Western Australia study found shelter dogs with aggressive tendencies exhibited less aggression toward humans after two weeks of taking CBD.

Seizures: Many anecdotal reports hail CBD’s success in combatting seizures in dogs, but the single controlled study delivered only moderate results. A Colorado State University study found CBD only worked with some dogs, and it reduced, but didn’t eliminate, seizures.

Other: Evidence from laboratory animals supports CBD’s effectiveness in promoting bone healing, fighting infection, treating inflammatory bowel disease, slowing degenerative myelopathy, quelling nausea and relieving pain.

Choosing Wisely

Broad-spectrum products work better than isolated CBD because they use the whole cannabis plant. Choose those with third-party certificates of analysis of potency and testing for heavy metals, mycotoxins or pesticides. Avoid human edible products that often contain ingredients such as xylitol that are toxic to pets.

Aim for about 0.1 to 0.2 milligram per kilogram of a dog’s weight, given twice daily by mouth. Work up gradually, but beware that more is not always better with CBD, because sometimes the response is biphasic—it doesn’t work if they get too little or too much. 

Discuss CBD with a veterinarian, but realize that not all of them are familiar or comfortable with the subject. CBD, like many supplements and drugs designed for humans and used on canines, is not yet approved by the U.S. Food and Drug Administration. 

Overall, the evidence is compelling that CBD can help some conditions. The endocannabinoid system is the largest system in the body and the least explored. CBD is not a miracle drug, but it may be the miracle our four-footed friends need.

Caroline Coile, Ph.D., is an award-winning writer of 34 books, thousands of magazine and web articles, and an app, All About Dogs.