CBD is a possible cause of diarrhea in dogs, although diarrhea is not the most common reaction. The problem may come from CBD itself, a high dose, the oil or flavoring in the product, or THC and other undeclared ingredients.
Merck Veterinary Manual records from January 2018 through February 2023 included diarrhea in about 3% of reported CBD exposure cases. That figure does not show the risk for every dog using CBD. Stop giving CBD until you speak with your veterinarian, especially if the diarrhea started soon after a dose.
CBD and Diarrhea in Dogs at a Glance
| Question | Short answer |
|---|---|
| Can CBD cause diarrhea? | Yes. Diarrhea is a reported adverse effect. |
| Is diarrhea common? | It appears to be uncommon, but the exact rate is unknown. |
| What should you do after diarrhea starts? | Do not give another dose until your veterinarian advises you. Keep water available and monitor your dog. |
| When is it an emergency? | Seek urgent veterinary care for bloody or severe diarrhea, repeated vomiting, marked lethargy, tremors, unsteadiness, collapse, or suspected THC exposure. |
| Is CBD approved for dogs? | The FDA has not approved cannabis or CBD products for use in animals. |
Why Can CBD Cause Diarrhea in Dogs?
CBD can affect a dog's digestive tract. Veterinary references list vomiting and diarrhea among the possible side effects of cannabidiol in dogs. Diarrhea may also occur after a dog receives too much CBD or consumes a product with ingredients that irritate the gut.
The product may be responsible rather than the CBD itself. Some commercial CBD products contain other ingredients, and testing has raised concerns about inaccurate labels and possible contaminants. A product labeled "hemp" or "CBD" may also contain measurable THC or other compounds.
How Often Does CBD Cause Diarrhea in Dogs?
The exact rate is unknown. CBD products for pets are not consistently standardized, and controlled safety data remain limited.
Merck Veterinary Manual reported diarrhea in about 3% of CBD-related cases recorded by the Pet Poison Helpline. These were reported exposure cases, not a risk estimate for all dogs that receive CBD.
Controlled studies offer some information but do not show that every CBD product is safe. In one 28-day study of healthy dogs, CBD was generally tolerated. The highest tested dose produced more gastrointestinal adverse events, mainly hypersalivation. In a separate six-month study, a THC-free CBD product was generally well tolerated in healthy dogs. More than half of the CBD-treated dogs developed a temporary increase in alkaline phosphatase, an enzyme associated with liver or bone activity.
What Should You Do If Your Dog Develops Diarrhea After CBD?
- Do not give another CBD dose until your veterinarian reviews the situation.
- Check the label for the CBD concentration, serving size, THC content, carrier oils, and other ingredients.
- Keep fresh water available. Diarrhea can cause dehydration.
- Contact your veterinarian if the diarrhea continues, returns after each dose, or occurs with vomiting, poor appetite, pain, or lethargy.
- Do not induce vomiting unless a veterinarian or animal poison-control professional tells you to do so.
If your dog is otherwise well and has had only one mild episode, your veterinarian may recommend observation and a short-term gastrointestinal diet. Frequent liquid stools lasting more than two days need veterinary attention. Severe or prolonged diarrhea can cause significant dehydration.
When Is CBD-Related Diarrhea an Emergency?
CBD-related diarrhea needs urgent veterinary care when it is severe, bloody, prolonged, or accompanied by other concerning symptoms. Seek care if your dog has:
- Bloody or black diarrhea
- Repeated vomiting
- Severe weakness, collapse, or difficulty standing
- Tremors, pronounced sleepiness, or unsteadiness
- Abdominal pain or a swollen abdomen
- Signs of dehydration, such as very dry gums or unusual weakness
- Diarrhea after eating a large amount of CBD
- Possible exposure to THC, marijuana, or an unknown cannabis product
Lethargy, ataxia, tremors, and urinary incontinence are more concerning for a large exposure, THC contamination, or another substance in the product than for a mild CBD side effect.
Could Something Other Than CBD Be Causing the Diarrhea?
Yes. Dogs can develop diarrhea after a diet change, eating garbage, stress, parasite exposure, infection, food intolerance, pancreatitis, inflammatory bowel disease, or an organ problem. A dog may also develop diarrhea after starting CBD without CBD being the cause.
Timing can provide a clue, but it does not prove the cause. CBD becomes more suspicious when:
- Diarrhea starts shortly after each dose.
- Diarrhea improves when CBD is withheld.
- No food, medication, or routine change explains the symptoms.
- Vomiting, drooling, lethargy, or another possible CBD-related sign occurs at the same time.
Is CBD Safe to Give Dogs?
CBD is not an FDA-approved treatment for dogs. The FDA has not approved cannabis for any use in animals and cannot confirm the safety, effectiveness, quality, or correct dosage of marketed animal CBD products.
Speak with a veterinarian before giving your dog CBD, especially if your dog has liver disease, takes seizure medication, pain medication, or other drugs, or is pregnant.