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Marijuana Poisoning - Olive’s Story

Olive’s owner thought nothing of the ‘thing’ Olive had eaten in the park on her morning walk, it wasn’t until much later when Olive collapsed that they realised that she was very unwell and needed urgent critical care.

Marijuana or Cannabis sativa/indica can be lethal for dogs as our ‘Star Pet of The Month’, Olive, found out earlier this month. But what is it, what are the effects it has on pets and how do we treat marijuana poisoning?

What Is Marijuana?

Marijuana or Cannabis sativa/Cannabis indica is used for recreational drug use and medicinal purposes. Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the two most commonly recognized, utilized, and studied cannabinoids although there are over 80 different cannabinoids in marijuana plants. The primary difference between the two is that THC causes psychotropic effects and has a moderate level of toxicity while CBD is non-psychotropic and is felt by many investigators to be non-toxic or have limited toxicity. The exact amount of each cannabinoid varies widely from strain to strain and plant to plant.

Cannabidiol is thought to have the following properties: anxiolytic, antipsychotic, antiemetic, anti-seizure, and anti-inflammatory. Medically, THC is used in an attempt to alleviate muscle spasms caused by multiple sclerosis, nausea from chemotherapy, weight loss in AIDS patients, seizure disorders and Crohn’s disease. Tetrahydrocannabinol is also used recreationally for its psychotropic effects.

Marijuana Poisoning

Animals can be poisoned by marijuana in different ways. They can ingest marijuana edibles such as brownies or pot butter, ingest the owner’s supply of marijuana (in any formulation), or by second-hand smoke. For poor Olive, it happened when she was on her morning walk and ingested it in the park.

Symptoms of Marijuana Toxicity

For Olive, the first sign that she was unwell, was when her dog walker came to take her out at lunchtime and they noticed she wasn’t her usual self and initially thought it was due to her being too hot. However, her condition deteriorated and at 6 pm Olive’s owner found her completely collapsed, incontinent, and unable to walk or lift her head, so she contacted Roundwood Vets for help.

Upon arrival, Olive could not walk into the surgery and had to be carried. Her bloods were taken immediately and came back remarkably normal. Due to Olive’s symptoms and history, the vets at Roundwood suspected she had eaten cannabis but didn’t want to rule out meningitis. Olive was extremely lethargic and kept whining, which was very distressing for her owner and family.

Other common symptoms of marijuana toxicity include:

  • Sedation/lethargy

  • Dilated pupils or glassed over eyes

  • Dazed expression

  • Difficulty walking and vomiting

Other, less common, symptoms can include:

  • Either a low or high heart rate

  • Vocalization such as whining or crying

  • Agitation

  • Tremors/Seizures

  • Trouble regulating temperature causing the body temperature to drop or rise

  • And, like Olive experienced, incontinence/dribbling urine

In severe cases, some pets can also become comatose.

Signs of toxicity can be seen anywhere from 5 minutes to 12 hours after the animal is exposed to marijuana. The signs can potentially last 30 minutes to several days depending on the dose ingested.


Although there is no true antidote for marijuana, veterinarians can give supportive care to help the pet through the clinical signs.

Taking your pet to the vet if they present this way is essential, vets can:

  • Regulate the temperature of the animal to ensure they aren’t too hot or cold and give fluids to help maintain hydration.

  • Give anti-vomiting medication to help stop fluid loss and closely monitor the animal’s heart rate to ensure that it is stable.

  • Help keep the pet comfortable and confined so they won’t be injured if they are having trouble walking.

  • In some cases, they may give your pet activated charcoal. This is a liquid that the animal drinks or is given that can help bind the toxin in the stomach or intestines to the charcoal and prevent absorption into the body.

Animals normally respond well with supportive care, however large ingestions of marijuana can be dangerous causing seizures and require intensive nursing care.

At Roundwood, Olive was closely monitored overnight by a nurse in case she started to have seizures (fit) or deteriorate further. She was also maintained on a high amount of intravenous fluids and provided with intensive nursing care.

A Happy Ending

Luckily for Olive, at 11 pm she started to show improvement and was able to stand and eat. By 2 am Olive was able to walk and slowly improved as the night went on. Olive made a full recovery by morning but it was a long night as she had to be closely monitored throughout.

If you suspect your pet has ingested marijuana or any other drug, don’t hesitate to contact us. Diagnosing and treating marijuana cases can often be hard to spot due to an incomplete history being given - this can be due to the drug stigma, legal repercussions or simply like Olive the owner not knowing what had been ingested. We at Roundwood are only interested in providing appropriate medical care. Giving accurate and complete medical history is imperative to provide necessary treatments and prevent unnecessary costs.

Find this article interesting? Read more on a similar topic and discover how Buster beat poisoning in the link below:


Order Dr Hannah Parkin's Amazing Guide To Caring For Your New Puppy.
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