A large observational study of 47,000 animals found that dogs receiving long-term cannabidiol supplements were reported by owners to show less intense aggression than dogs not given CBD, researchers said. The work, published Nov. 28, 2024, and discussed again in early December 2024, suggests sustained CBD use may produce measurable behavioral change in some canines.

The study, published in Frontiers in Veterinary Science, analyzed owner-reported health and behavior across a wide cohort and compared dogs on long-term CBD products with those that were not. Dr. Julia Albright, an associate professor at the University of Tennessee College of Veterinary Medicine, said, “This long-term behavioral change highlights the potential of CBD as a therapy for canine behavioral issues.” Research on CBD in pets is still limited and mixed, with a few controlled studies suggesting potential benefits but significant methodological caveats.

Dr. Maxwell Leung, director of the Cannabis Analytics, Safety and Health Initiative at Arizona State University, described a pattern the researchers observed: “Behaviorally, dogs given CBD products for multiple years are initially more aggressive compared to dogs not receiving those products, but their aggression becomes less intense over time.” That finding, the team said, points to change across an extended treatment period rather than an immediate calming effect, a critical distinction for understanding how CBD may be beneficial.

The dogs receiving CBD in the analysis tended to be older on average — about three years older than the comparison group — and had higher reported rates of certain health conditions: dementia in 18% of the CBD group, joint problems in 13%, and cancer in 10%. According to a large 2025 study of over 43,000 U.S. dogs, about 55.6% of dog owners reported aggression-related behavior problems in their pets. The researchers emphasize these statistics as descriptive of the population taking CBD products rather than proof of causation.

Dr. Albright offered context on the behavior measured: “Most canine aggression is related to underlying stress or anxiety — a fight or flight response that kicks in. It is unclear why only aggression but not other types of anxious or agitated behaviors seemed to be improved with CBD treatment.” Pet owners should first consult a veterinarian, as CBD products for animals are not FDA-approved, dosing is not standardized, and CBD can interact with other medications or underlying health conditions.

The authors noted that CBD is a component of marijuana that does not cause intoxication, and that observed behavioral shifts were most apparent with long-term, consistent supplementation. Dr. Leung added, “There are many similarities in how CBD can benefit dogs and humans medically.” This underscores the need for careful consideration when introducing such supplements to a pet’s regimen.

The paper’s publication in Frontiers in Veterinary Science drew attention to the dataset and methods used; the journal entry is available through Frontiers’ site. The American Kennel Club was noted by the study’s authors as a provider of information on CBD for dog owners, and the research team scheduled an announcement about the findings on Friday, Dec. 5, 2025. The story record was updated Dec. 9, 2025, at 6:23 am.

Researchers framed their results as observational: they describe associations between reported long-term CBD use and changes in aggression intensity across a large group of animals rather than definitive, controlled proof of effectiveness. The study’s scale, covering data on 47,000 animals, gives weight to the patterns the authors identified while leaving further work to test mechanisms and treatment protocols.

The publication adds to a growing body of research exploring medical applications of cannabidiol in veterinary contexts and highlights areas for targeted clinical trials.