Cannabis oil for dogs helps control itching and allows for oclacitinib dose reduction, Brazilian study finds

A clinical study conducted by Brazilian researchers investigated the use of cannabis for dogs with atopic dermatitis and identified a reduction in pruritus (itching) during adjuvant treatment with full-spectrum Cannabis sativa oil, rich in cannabidiol (CBD). The study also observed the maintenance of itch control after a 50% reduction in the dose of oclacitinib (Apoquel), a medication used to treat the condition. The work was published on October 14, 2026, in the journal Frontiers in Allergy.

Canine atopic dermatitis is a chronic, multifactorial inflammatory disease with a genetic component that causes intense itching, skin lesions, and impairs the animals' quality of life. Treatment is multimodal and may require continuous monitoring. Oclacitinib, a Janus kinase (JAK) inhibitor, is widely used, but some dogs do not achieve satisfactory symptom control. In this scenario, modulation of the skin's endocannabinoid system emerges as an investigated strategy.

How the study was conducted (cannabis for dogs)

The research, led by Carollina Mariga and a team from the Universidade Federal de Santa Maria (UFSM), with the participation of researchers from the Universidade Federal de Santa Catarina (UFSC), followed 16 dogs diagnosed with atopic dermatitis who presented persistent itching despite the use of oclacitinib. Fourteen animals completed all stages of the protocol.

The study adopted a prospective repeated-measures design, in which each dog served as its own control. The animals went through four stages:

• T0: treatment with oclacitinib alone, at an individualized dose;
• T30: oclacitinib combined with placebo, consisting of mineral oil;
• T60: full-dose oclacitinib combined with cannabis oil, administering 2 mg/kg of CBD twice daily;
• T90: continuation of cannabis oil with a 50% reduction in the oclacitinib dose.

The oil used was full-spectrum, rich in CBD, with a reported concentration of 500 mg in 30 mL. The product was donated by Hippie Hounds Treats and used under research authorizations from the Agência Nacional de Vigilância Sanitária (Anvisa).

Both the veterinary dermatologist responsible for the evaluations and the pet owners were unaware of whether the administered bottle contained placebo or cannabis oil, a procedure used to reduce potential biases in assessments.

Key findings

There was no statistically significant difference in skin lesion scores, assessed by the CADESI-4 index, across the study stages. However, pruritus, evaluated by owners on a 0 to 5 scale, showed a statistically significant reduction between the baseline of the study (T0) and the cannabis treatment phases (T60 and T90).

The planned primary comparison between the placebo phase (T30) and the introduction of cannabis oil (T60), however, did not reach statistical significance. Nor was there any statistically significant worsening of itching observed between T60 and T90, even after the 50% reduction in the oclacitinib dose.

Reported adverse effects included lethargy, soft stools, vomiting, and, in one case, agitation. According to the researchers, the episodes were mild, transient, and self-limiting. Clinical signs were also recorded during the placebo phase, which reinforces the need for caution when attributing effects exclusively to the cannabinoid.

Following the discontinuation of cannabis oil while maintaining the reduced dose of oclacitinib, nine of the 14 dogs that completed the protocol experienced a return of itching within seven days. The other five remained pruritus-free during this period. In addition, nine owners, representing 56.25% of the total 16 initially enrolled participants, chose to continue cannabis treatment after the study concluded.

What this means in practice

The authors conclude that the adjuvant use of cannabis oil was associated with a reduction in pruritus compared to baseline, and that itch control was maintained during the period when the oclacitinib dose was cut in half. The findings support further investigation of cannabinoids as part of a multimodal strategy for managing canine atopic dermatitis, especially in animals that do not achieve satisfactory control with conventional treatment.

Even so, the study has important limitations: a small sample size, a fixed sequence of treatments, and the lack of a statistically significant difference between placebo and cannabis in the primary pruritus comparison. Because all dogs went through the same stages in the same order, it is not possible to reliably separate the effects of the treatment from potential natural fluctuations of the disease over time.

The researchers emphasize the need for further controlled clinical trials on cannabis for dogs, featuring larger cohorts and more robust methodological designs, to confirm the results and elucidate the potential oclacitinib-sparing effect, as well as to establish more appropriate dosages, formulations, and protocols.

For Brazilian veterinary medicine, the study adds clinical data to research on cannabis for dogs. While the findings are promising, they do not, on their own, establish a treatment protocol nor justify reducing medication without veterinary supervision.