The pet CBD market reached an estimated $629 million in U.S. sales in 2024, according to Brightfield Group, and is projected to exceed $1 billion by 2027. Pet owners are purchasing CBD tinctures, treats, topicals, and chews at rapidly accelerating rates, driven by the same wave of consumer enthusiasm that powers the human CBD market — but with even less regulatory oversight and, in some areas, even less scientific evidence.

The critical question for any pet owner considering CBD is not whether the marketing is compelling — it is. The question is what the veterinary evidence actually supports, what the risks are, and how to navigate a market where quality varies enormously and regulatory guardrails are minimal.

Animals Have Endocannabinoid Systems Too

The most fundamental point about cannabinoids and animals is that the endocannabinoid system (ECS) is not unique to humans. It is present in all vertebrates and even some invertebrates. Dogs, cats, horses, and other mammals have a fully functional ECS comprising CB1 receptors (concentrated in the brain and central nervous system), CB2 receptors (concentrated on immune cells and in peripheral tissues), endogenous cannabinoids (anandamide and 2-AG), and the enzymes that synthesize and degrade them (FAAH and MAGL).

This means that plant-derived cannabinoids — CBD, THC, and others — interact with receptors and signaling pathways in animals just as they do in humans. The pharmacological mechanisms are conserved across mammalian species.

However, there are significant species-specific differences that have direct practical consequences.

Dogs have a higher density of CB1 receptors in the cerebellum and brainstem compared to humans. This is believed to be the reason dogs are substantially more sensitive to THC than humans are. THC produces more pronounced neurological effects in dogs — including ataxia (loss of coordination), disorientation, and in severe cases, coma — at doses that would produce only mild effects in humans.

Cats have a different metabolic profile for cannabinoids compared to dogs. Cats lack certain hepatic glucuronidation enzymes that are involved in processing CBD and THC metabolites. This means cannabinoid clearance is slower in cats, and the effective dose and duration of effect differ from dogs. Less research has been conducted on CBD in cats than in dogs.

Horses have received increasing attention in the equine sports and veterinary world, and limited studies have examined CBD pharmacokinetics in horses. The available data suggest that horses metabolize CBD differently than small animals, with longer plasma half-lives and different bioavailability profiles depending on route of administration.

THC Toxicity in Dogs: A Serious Concern

Before discussing CBD’s potential benefits, the THC toxicity issue requires clear emphasis because it is the most important safety consideration for pet owners.

Dogs are significantly more sensitive to THC than humans. The ASPCA Animal Poison Control Center reports that cannabis toxicity calls involving pets have increased dramatically with the expansion of cannabis legalization and the proliferation of edibles in homes. The majority of cases involve dogs that have ingested THC-containing edibles, flower, or concentrates.

Signs of THC toxicity in dogs include: lethargy and depression, ataxia (staggering, inability to walk normally), dribbling urine (urinary incontinence), dilated pupils, exaggerated startle response, tremors, hypothermia, bradycardia (slow heart rate), and in severe cases, seizures and coma.

The minimum lethal dose of THC in dogs has been estimated at approximately 3 grams per kilogram of body weight in published veterinary toxicology literature — a very high dose that is unlikely to be reached through accidental ingestion in most circumstances. However, dogs have died after ingesting highly concentrated cannabis products (particularly butter or oil infusions used for edibles, which can contain thousands of milligrams of THC in a small volume) or when THC ingestion is complicated by chocolate toxicity (since many edibles are chocolate-based) or xylitol (an artificial sweetener toxic to dogs that is sometimes present in gummy edibles).

The practical takeaway is absolute: THC-containing products must be kept securely away from dogs. This is not a theoretical concern. Emergency veterinary clinics in legal cannabis states report treating cannabis-toxicated dogs on a regular basis.

CBD products intended for pets should contain zero or near-zero THC. The standard threshold in the pet CBD industry is less than 0.3% THC — the same threshold used to define legal hemp for humans. Full-spectrum pet CBD products exist and technically contain trace THC, but the amounts should be pharmacologically insignificant at recommended pet doses. Products with higher THC content are inappropriate for animals.

What the Veterinary Research Shows

Veterinary research on CBD is more limited than human research, but it has grown substantially since 2018. The conditions with the most evidence are osteoarthritis pain and epilepsy in dogs.

Osteoarthritis in Dogs

The strongest veterinary evidence for CBD comes from studies of osteoarthritis pain in dogs. This is clinically relevant because osteoarthritis affects an estimated 25% of dogs and is a leading cause of chronic pain and reduced quality of life in older animals.

A landmark 2018 study published in Frontiers in Veterinary Science by researchers at Cornell University examined CBD oil (2 mg/kg twice daily) in dogs with osteoarthritis in a randomized, placebo-controlled, double-blind crossover design — the gold standard in clinical research. The results showed statistically significant increases in comfort and activity levels as measured by veterinary assessment and owner-reported scores. No observable side effects were detected at this dose. The study is frequently cited as the strongest evidence for CBD efficacy in veterinary medicine.

A subsequent 2020 study, also published in Frontiers in Veterinary Science, examined CBD at 2 mg/kg and 8 mg/kg in dogs with osteoarthritis over a 4-week period. Both doses produced improvements in pain and mobility scores compared to baseline. The higher dose produced greater improvements but also a higher incidence of mild gastrointestinal side effects (soft stool, mild diarrhea). Liver enzyme elevations (specifically alkaline phosphatase, or ALP) were noted in some dogs at both doses — a finding that has been replicated across multiple studies and requires monitoring.

A 2022 study in the Journal of the American Veterinary Medical Association examined CBD (2.5 mg/kg twice daily) as an adjunctive therapy alongside standard NSAID treatment (meloxicam) in dogs with osteoarthritis. The combination group showed greater improvement in pain scores than either therapy alone. This suggests that CBD may have additive or synergistic effects with conventional pain medications — an approach that could allow lower NSAID doses and reduced NSAID side effects.

Epilepsy in Dogs

Idiopathic epilepsy affects an estimated 0.5% to 5% of dogs, depending on breed. Standard anticonvulsant medications (phenobarbital, potassium bromide, levetiracetam) are effective but carry significant side effect profiles including sedation, liver damage, and behavioral changes.

The most rigorous veterinary study of CBD for epilepsy was conducted at Colorado State University and published in the Journal of the American Veterinary Medical Association in 2019. In this randomized, double-blind, placebo-controlled trial, 26 dogs with treatment-resistant epilepsy received either CBD (2.5 mg/kg twice daily) or placebo for 12 weeks in addition to their existing anticonvulsant medications. The CBD group showed an 89% reduction in seizure frequency compared to a 43% reduction in the placebo group. However, the difference in responder rate (proportion of dogs achieving 50% or greater seizure reduction) was not statistically significant — 2 of 12 in the CBD group vs. 0 of 9 in the placebo group.

The seizure frequency reduction was clinically meaningful, and the lack of statistical significance in the responder analysis was likely due to the small sample size. Larger studies are underway. Based on this and supporting evidence, the FDA in 2024 issued a study-backed determination that CBD showed potential as a veterinary therapeutic, though no CBD products have received formal FDA approval for veterinary use as of early 2026.

Anxiety in Dogs

Anxiety — including separation anxiety, noise phobia (thunderstorms, fireworks), and generalized anxiety — is one of the most common reasons pet owners report purchasing CBD products. The evidence base here is thinner than for pain or epilepsy.

A 2020 study published in the Journal of the American Holistic Veterinary Medical Association evaluated CBD treats in dogs with anxiety behaviors. The study found improvements in owner-reported anxiety scores, but the study was open-label (not blinded or placebo-controlled), which limits the reliability of the findings.

A more rigorous 2023 study examined CBD (4 mg/kg once daily) for noise-related anxiety in dogs exposed to firework recordings. The CBD group showed reduced cortisol levels (a physiological stress marker) compared to placebo, but behavioral measures of anxiety were not significantly different between groups. The authors suggested that CBD may modulate the physiological stress response without necessarily changing observable behavior — an interesting finding that complicates outcome measurement.

CBD in Cats

Feline research lags significantly behind canine research. The most relevant study, published in 2019 in the journal Animals, examined CBD pharmacokinetics in cats and found that oral CBD at 2 mg/kg was well-tolerated but produced lower and more variable blood levels compared to dogs at the same dose. Cats also showed more pronounced side effects — including excessive licking and head shaking — which the authors attributed to the taste of the CBD oil formulation rather than pharmacological effects.

A 2021 pilot study examined CBD for osteoarthritis in cats and found owner-reported improvements in activity and comfort, but the study was small (20 cats), open-label, and short-duration (6 weeks). The authors recommended larger controlled studies before clinical conclusions could be drawn.

The practical reality is that CBD evidence in cats is preliminary. Cat owners considering CBD should approach it with greater caution than dog owners, use lower doses (starting at 1 mg/kg rather than 2 mg/kg), and monitor carefully for adverse effects.

Dosing by Weight: A Practical Framework

Unlike human CBD products, where dosing is often arbitrary and label-driven, veterinary CBD dosing benefits from the weight-based frameworks standard in veterinary medicine.

The most commonly studied and referenced dose range for dogs is 1 to 5 mg per kilogram of body weight per day, typically divided into twice-daily administration.

Starting dose: 1 mg/kg twice daily. This is the conservative starting point supported by safety data across multiple studies. For a 30-pound (13.6 kg) dog, this translates to approximately 13 to 14 mg per dose, or 27 to 28 mg per day.

Moderate dose: 2 mg/kg twice daily. This is the dose used in the Cornell osteoarthritis study and the Colorado State epilepsy study. It represents the best-supported dose for therapeutic effect with acceptable safety. For a 30-pound dog: approximately 27 mg per dose, 54 mg per day.

Higher dose: 5 mg/kg twice daily. This represents the upper range studied in veterinary trials. Higher doses produced greater effects in some studies but also increased the incidence of side effects, particularly GI issues and liver enzyme elevation. This dose should be used only under veterinary supervision.

For cats: Start at 1 mg/kg twice daily and increase cautiously. Pharmacokinetic differences suggest cats may need lower doses than dogs for equivalent blood levels, but the limited data makes precise dosing recommendations less reliable.

For all species: The principle of “start low and go slow” applies. Begin at the lowest recommended dose, maintain for 1 to 2 weeks to observe effects, and increase incrementally if needed. Effects on chronic conditions like osteoarthritis may not be apparent for 2 to 4 weeks.

The Liver Enzyme Question

Across multiple veterinary CBD studies, elevation of alkaline phosphatase (ALP) has been consistently reported. ALP is a liver enzyme that is commonly monitored in veterinary bloodwork, and elevations can indicate liver stress or damage.

In the Cornell osteoarthritis study, 9 of 16 dogs receiving CBD showed ALP elevations. In the Colorado State epilepsy study, some dogs showed ALP increases. A 2020 long-term safety study published in the journal Animals found that ALP elevations were common with CBD administration at 2 mg/kg but stabilized over time and were not associated with clinical signs of liver disease.

The clinical significance of CBD-associated ALP elevation remains debated. ALP can be elevated by many factors in dogs — corticosteroid use, breed predisposition (Scottish Terriers have naturally higher ALP), bone growth in young dogs, and benign nodular hyperplasia in older dogs. Whether CBD-associated ALP elevation indicates genuine hepatotoxic risk or benign enzyme induction is not definitively established.

The consensus recommendation from veterinary researchers is that dogs receiving CBD should have baseline liver enzyme panels before starting CBD and follow-up panels at 2 weeks, 1 month, and every 3 to 6 months thereafter. If ALP elevations are persistent and progressive, or if other liver enzymes (ALT, GGT) also elevate, dose reduction or discontinuation should be considered.

This monitoring recommendation is particularly important for dogs on other medications that affect liver function, including phenobarbital, NSAIDs, and certain chemotherapy agents.

Drug Interactions

CBD is metabolized by cytochrome P450 enzymes in the liver — the same enzyme family that metabolizes many pharmaceutical drugs. CBD can inhibit certain P450 enzymes (particularly CYP2D6 and CYP3A4), potentially altering the metabolism and blood levels of co-administered medications.

In veterinary practice, the most relevant potential interactions include:

Phenobarbital — Used for epilepsy. CBD may increase phenobarbital blood levels by inhibiting its metabolism, potentially increasing sedation and toxicity risk. The Colorado State epilepsy study noted this interaction and recommended monitoring phenobarbital levels when adding CBD.

NSAIDs (meloxicam, carprofen, deracoxib) — Used for pain and inflammation. Both NSAIDs and CBD affect liver function, and the combination requires liver enzyme monitoring. The JAVMA study on adjunctive CBD with meloxicam did not find increased adverse effects, but monitoring was conducted.

Gabapentin — Increasingly used for chronic pain and anxiety in pets. Potential for additive sedation when combined with CBD.

Any pet on pharmaceutical medications should not start CBD without consulting a veterinarian who can assess potential interactions. This is not a formality — it is a safety necessity.

The pet CBD market is flooded with products of wildly variable quality. The FDA does not regulate pet CBD products for safety or efficacy, and testing by consumer advocacy groups and media outlets has repeatedly found products that contain less CBD than labeled, more THC than labeled, or contaminants including heavy metals, pesticides, and residual solvents.

Quality indicators to look for:

Third-party lab testing (Certificate of Analysis). This is the minimum baseline. A reputable pet CBD product provides a recent COA from an independent lab showing cannabinoid content (confirming CBD amount and THC levels below 0.3%), contaminant testing (pesticides, heavy metals, mycotoxins), and residual solvents. If a company cannot or will not provide a COA, do not purchase the product.

Hemp-derived CBD with THC below 0.3%. As discussed above, THC poses a genuine risk to dogs. Products should clearly state THC content, confirmed by COA.

Species-specific formulation. Products formulated for pets typically use carrier oils and flavorings appropriate for animals (MCT oil, salmon oil) rather than human formulations that may contain ingredients toxic or unpalatable to pets.

Clear dosing instructions based on weight. Products that provide per-pound or per-kilogram dosing guidance are more trustworthy than those offering vague instructions.

NASC Quality Seal. The National Animal Supplement Council provides a quality seal program for animal supplements including CBD products. Companies with the NASC seal have undergone facility audits and adverse event reporting commitments. This is not a guarantee of efficacy, but it indicates a higher baseline of manufacturing quality.

Avoid products with bold medical claims. FDA regulations prohibit marketing CBD products — human or animal — with disease treatment claims. Companies that claim their products cure, treat, or prevent specific diseases are violating federal regulations and demonstrating a willingness to operate outside legal boundaries.

What Veterinarians Can and Cannot Do

The legal landscape for veterinarians regarding CBD is complicated and varies by state.

In many states, veterinarians are now legally permitted to discuss CBD with clients and recommend CBD products for animal patients. This is a relatively recent development — as recently as 2019, some state veterinary boards considered CBD discussions to constitute prescribing an unapproved substance, potentially putting veterinary licenses at risk.

California passed AB 2215 in 2018, explicitly protecting veterinarians who discuss cannabis use for animal patients from disciplinary action. Other states have followed with similar protections. As of 2025, veterinarians in most legal cannabis states can discuss CBD products with clients without professional risk.

However, no veterinarian can formally prescribe CBD because it is not an FDA-approved veterinary drug. Recommendations are just that — recommendations, not prescriptions. This means pet CBD products are purchased as supplements rather than medications, and they are subject to supplement-level (rather than pharmaceutical-level) quality control.

The American Veterinary Medical Association (AVMA) has published position statements acknowledging the growing evidence base for veterinary CBD use while emphasizing the need for more research and the importance of veterinary involvement in dosing and monitoring decisions. The AVMA supports the right of veterinarians to discuss CBD with clients and has advocated for regulatory pathways that would allow formal approval of cannabinoid-based veterinary therapeutics.

An Honest Assessment

The evidence supports CBD as a promising adjunctive therapy for certain conditions in dogs — particularly osteoarthritis pain and potentially epilepsy. The evidence in cats is preliminary but suggests similar mechanisms with different pharmacokinetics. The safety profile at studied doses is generally favorable, with liver enzyme elevation being the primary concern requiring monitoring.

What the evidence does not support is CBD as a cure-all for every pet ailment, a substitute for veterinary care, or a risk-free supplement that can be administered without professional guidance. The marketing of pet CBD products frequently outpaces the evidence, and pet owners should apply the same critical assessment to pet CBD claims that they would to any other health product.

The responsible approach is to consult a veterinarian before starting CBD, use products with verified third-party testing, start at conservative doses, monitor for adverse effects, and maintain realistic expectations about outcomes. Your pet deserves evidence-based care, and the evidence — while growing — still requires the guidance of a professional who understands your specific animal’s health profile.