Marijuana (cannabis) is toxic to dogs. Its active compound, THC, affects their nervous system and can cause anything from incoordination and drowsiness to tremors or seizures. If you suspect your dog has eaten marijuana in any form, it is an emergency: call us on +34 942 51 00 66 (24h emergencies on +34 722 61 44 10).
Our veterinarian María Fernández discussed this problem on Antena 3 Noticias, following several cases of dogs poisoned in the Somo area after eating faeces from people who use cannabis.
Interview with our veterinarian María Fernández on Antena 3 Noticias (5 July 2026).
How does a dog get intoxicated with marijuana?
Dogs can be poisoned by cannabis in several ways, and it is not always obvious to the owner:
- Eating the substance directly: buds, hashish, oils or, above all, edibles (cookies, brownies, gummies), which often also contain chocolate or sweeteners such as xylitol, toxic in their own right.
- Ingesting faeces from cannabis users: THC is partly eliminated in faeces, and a dog that eats them during a walk can be poisoned. This is what has caused several cases in the Somo area.
- By inhaling smoke in enclosed spaces, although this is less common.
Dogs are more sensitive to THC than people: they have more receptors for this substance in the brain, so amounts that would seem small to an adult can affect them significantly.
Symptoms of marijuana poisoning in dogs
Signs usually appear between 30 minutes and 3 hours after ingestion and can last from several hours to a couple of days. The most common are:
- Incoordination when walking (ataxia), as if the dog were "drunk".
- Drowsiness and lethargy, or on the contrary, agitation and restlessness.
- Involuntary urine dribbling: a very characteristic sign of this poisoning.
- Dilated pupils and a vacant stare.
- Hypersensitivity to noise and touch, with startling or tremors.
- A drop in body temperature and heart rate.
- Drooling, vomiting or loss of appetite.
- In severe cases: intense tremors, seizures or loss of consciousness.
None of these signs is exclusive to cannabis, so the diagnosis is always confirmed by the vet by assessing the animal and the information you provide.
“If you suspect your dog has eaten marijuana, don't wait to see how it develops: call us. With timely care, the vast majority recover with no lasting effects.”
What to do if your dog has eaten marijuana
- Go to or call your vet immediately. It is an emergency; the sooner it is assessed, the better. Our emergency number is +34 722 61 44 10.
- Tell them honestly what your dog has eaten and, if you know, how much and when. It is not a legal issue, it is key medical information to treat it well and fast. Hiding it only delays treatment.
- Do not try to make it vomit on your own or give home remedies: depending on the animal's condition it can be dangerous. Leave that decision to the vet.
- Keep it in a calm, warm and safe place while you get there, to prevent it from falling or hurting itself.
Is it serious? Can my dog die?
With timely veterinary care, the prognosis is usually good and most dogs recover fully. There is no antidote: treatment is supportive (temperature control, hydration, monitoring and, where appropriate, measures to reduce absorption of the toxin).
The risk increases with high doses, with small dogs or puppies, and especially with edibles, which can add the toxicity of chocolate or xylitol. So even if mild cases seem to pass, it is always worth consulting: it is how to rule out complications.
Assess each specific case with your vet; the appropriate treatment depends on the age, weight, health status and history of each animal.
How to prevent cannabis poisoning
- Keep any cannabis product out of the dog's reach, especially edibles.
- During walks, watch what it sniffs and puts in its mouth, especially in nightlife areas or parks where there may be remains.
- Work on the "drop" or "leave it" command so it releases what it picks up from the ground.
- At the slightest doubt that it may have ingested something, consult as soon as possible.
If you think your dog has been poisoned, come to Clínica Veterinaria Somo
At Clínica Veterinaria Somo, in Somo (Cantabria), we handle veterinary emergencies 24 hours a day for dogs and cats. If you suspect poisoning, do not wait: call us on +34 942 51 00 66 or the emergency line +34 722 61 44 10 and come in as soon as possible. Tell us what has happened and we will get ready to receive your pet.
