Cannabis (THC) toxicity in dogs is becoming increasingly common in the UK as cannabis products become more accessible. Dogs are far more sensitive to THC than humans. Even small amounts can lead to symptoms, such as wobbliness, sedation, dilated pupils and changes in behaviour.  All dogs are vulnerable, but young and curious adult dogs are most at risk. Talk to a vet without delay if your dog has consumed a cannabis product.

Cannabis toxicity (marijuana poisoning, THC intoxication) happens when dogs ingest or inhale products containing tetrahydrocannabinol (THC), the psychoactive chemical found in the leaves and flowers of the cannabis plant. Edible cannabis products, such as gummies and cannabis ‘cakes’ are especially risky due to high concentration of THC and the presence of additional toxins, such as chocolate or xylitol (an artificial sweetener). With supportive care, most dogs will recover within 1–3 days, but severe cases and dogs who’ve consumed products containing additional toxins will usually need veterinary hospital treatment.

What is cannabis (THC) toxicity in dogs?

Cannabis toxicity in dogs occurs when they are exposed to THC, the psychoactive chemical in marijuana. 

The leaves and flowers of the cannabis plant contain 2 chemical compounds:

1. Tetrahydrocannabinol (THC): A psychoactive drug that acts on the brain to alter mood, thought processes and perception; a popular ‘recreational drug’ in the UK.

2. Cannabidiol (CBD): A non-psychoactive chemical, widely used in the UK for people and pets to aid relaxation, relieve pain, reduce anxiety, and improve sleep.

Hemp oil is extracted from the seeds of the cannabis plant. Hemp oil doesn't contain CBD or THC.

Dogs are exposed to cannabis toxicity by any of the following:

• Consuming edible products containing THC, such as brownies or gummies

• Consuming cannabis oils/drops

• Inhaling smoke when humans smoke marijuana in enclosed environments or poorly-ventilated rooms

• Accessing discarded or poorly-stored concentrates or vape cartridges which have a high-potency THC content

• Consuming human faeces that contains THC waste (rare but reported)

Dogs are more sensitive to the effects of THC than humans because they have more receptors for the drug in their brains than humans do.

Symptoms can develop within half an hour and may worsen quickly, especially if your dog ate a cannabis ‘food product’ or concentrate. Talk to a vet without delay. The sooner your dog receives treatment, the better the outlook for prompt recovery. 

Symptoms of cannabis toxicity in dogs

Signs usually begin between 30 minutes to several hours after exposure.

• Becoming wobbly/unsteady on their feet (ataxia)

• Appearing very sleepy or sedated

• Dilated pupils / glassy eyes

• Dribbling or incontinence

• Vomiting or drooling

• Becoming oversensitive to sound or touch

• Trembling or twitching

• Low body temperature 

• Becoming agitated or vocalising, occasionally aggressive.

Severe cases may progress to collapse, seizures, changes/difficulty in breathing, and coma.

Are some dogs more at risk of cannabis toxicity than others?

All dogs are susceptible to the effects of THC. However, some will have a relatively greater risk:

• Young and inquisitive dogs: more likely to scavenge food items, chew discarded vapes, containers, etc

• Small breeds: their lower body weight increases the risk from small doses

• Dogs with heart disease or neurological problems: the action of THC may worsen clinical signs

• Dogs living in towns and cities: greater risk of exposure risk

• Households using edible cannabis products or concentrates: higher THC potency in these and risk of additional toxin exposure with edibles

Safe treats for dogs

How is cannabis toxicity diagnosed in dogs?

Vets diagnose cannabis toxicity based on the history of possible exposure and your dog’s symptoms.

Your vet may also:

• Carry out a full physical and neurological exam

• Check any packaging for THC concentration or added toxins

• Run blood tests

• Check blood glucose

• Perform urine analysis

• Monitor your dog’s heart rate and blood pressure

Human drug tests for the presence of cannabis are unreliable in dogs and often give false negative results.

What’s the treatment for cannabis toxicity in dogs?

There’s no cure or antidote for THC toxicity. Treatment focuses on providing supportive care and controlling symptoms while your dog’s body removes the chemical and recovers. 

Mild cases may recover at home with careful monitoring, but moderate to severe cases require hospital care. This may include:

• Intravenous fluids

• Anti-nausea medication

• Monitoring and controlling body temperature

• Sedation if symptoms include agitation

• Seizure control medication in severe cases

• Intravenous lipid emulsion (ILE) therapy for severe cases with life-threatening symptoms. ILE ‘draws’ TLH out of tissues and into the bloodstream, where it’s carried to the liver for processing and removal.

• Oxygen therapy or ventilatory support (in rare, extreme cases)

Most dogs make a full recovery within 24–72 hours.

How to look after a dog with cannabis toxicity at home

Always talk to a vet if you suspect your dog has been exposed to cannabis. Your vet may advise monitoring at home for mild cases. Note that even if your dog looks “chilled out,” they may be wobbly, uncoordinated and at risk of injury.

• Prevent further exposure: remove any cannabis products, or remove your dog from a contaminated environment

• Let your dog rest in a quiet, dimly-lit room

• Block off access to stairs or other hazards

• Provide easy access to fresh water

• Offer them small bland meals if they are fully alert

• Watch their breathing and check they are still responsive

Never attempt to induce vomiting at home. This is particularly dangerous in drowsy or wobbly dogs, who will be vulnerable to choking or aspiration.

Tips on how to prevent cannabis toxicity in dogs

• Store cannabis products securely and out of reach

• Avoid leaving edible cannabis products unattended in accessible locations

• Remind guests to secure their belongings!

• Avoid smoking or vaping around pets

• Supervise your dogs on walks in public areas, especially if they are likely to scavenge ‘interesting’ objects

• Dispose of waste safely

Is my family at risk of catching cannabis toxicity?

No. Cannabis toxicity is not contagious. However, safe storage is essential to protect children and pets.

• Store products in child-proof containers

• Avoid second-hand smoke exposure

• Keep rubbish bins secure

Cannabis products in the home

CBD oil has become hugely popular in products to treat pain, anxiety and depression in people and pets. THC may be present, but the levels are low and legally regulated to prevent toxicity.

• Many CBD oil products are available over the counter, without a prescription.

• CBD oils sold across the counter should have no more than a legal maximum of THC.

• CBD oil should not cause harmful effects if your dog swallows some; they may become slightly drowsy or eat a little more than normal.

• Symptoms of toxicity from CBD oil suggest that the actual THC level may be higher than the label suggests and above the legal limit.

Talk to a vet without delay if you are concerned that your dog shows symptoms of toxicity.

When you should be worried about cannabis toxicity in dogs

Seek help from a vet immediately if your dog is :

• Unconscious or difficult to rouse

• Having seizures or tremors

• Having difficulty breathing 

• Very weak or collapsed

• Suspected to have eaten a cannabis product also containing chocolate or xylitol

• Vomiting repeatedly

• Getting worse as time goes on

Joii can help with:

• Advise following suspected ingestion, without symptoms or mild ones only

• Home care following treatment

• Monitoring recovery

• Keeping your dog safe