Cannabis for Canines: Is THC Bad for Dogs?

Humans find intoxication quite pleasurable, enticing even! But, like chocolates and almonds, marijuana is an absolute NO-NO for dogs. 

While both humans and dogs can consume marijuana products and experience a “high” – which is a strong, psychedelic euphoria – or more commonly known as a trippy feeling, dogs don’t feel any kind of pleasure. 

They feel confused, experience breathlessness, and even suffer from what vets call “marijuana poisoning” – none of which are pleasant to the animal in any way! 

While admittedly all cannabinoids, including both CBD and THC, have several health benefits for animals and humans alike, dogs can’t handle the psychoactive effects of THC or delta-9-tetrahydrocannabinol. 

What’s THC?

THC or delta-9-tetrahydrocannabinol is the main psychoactive chemical compound of cannabis plants. It is known for the much-famed “marijuana high”. Although cannabis has over 400 active cannabinoids, most cannabis strains grown as marijuana contain high levels of THC, even up to 30%.

When we consume cannabis in any form, the THC in these plants activates our body’s endocannabinoid system by binding with CB1 receptors, which are found across the body, especially in our brain. This triggers a strong reaction that may be described as a psychedelic euphoria, colloquially known as a “high” or “stone”.

Like humans, our pets can feel this too. However, unlike us, they don’t enjoy it. In fact, it can be quite scary for them. They feel disoriented, sick, unsure of their steps and even dash into objects, like furniture, in their attempts to regain their balance. 

Does THC have any health benefits?

Yes, like all active cannabinoids, THC, too, has quite a few health benefits. They are…

  1. Provides relief from pain: Research shows THC is an effective analgesic [1]. According to studies, THC can help manage both nociceptive and neuropathic pain [2]. It is also effective in treating chronic pain [3, 7] associated with arthritis, fibromyalgia [4], and multiple sclerosis [9, 10]. Studies show that THC triggers the release of agmatine, which controls an individual’s pain threshold [8]
  2. Acts as an antiemetic agent: Nausea, vomiting, and appetite loss are some irritating symptoms that can accompany both mild and severe conditions. THC has been found to be particularly effective in curbing these issues, especially among cancer [5] and AIDS patients undergoing treatment. Synthetic THC isolates, like Marinol [6], which has been in use since the 1980s, is quite effective. Inhalation of THC by male HIV patients has shown a remarkable reduction in peptide PYY levels (appetite suppressant) and an increase in leptin and ghrelin levels (appetite inducers) [11].  
  3. Provides neuroprotection: Most people think THC is harmful to your brain. However, some studies have shown evidence that THC can also positively impact your brain cells. Studies have proved that chronic use of THC among mice promotes neurogenesis or brain cell growth and development in the hippocampus [12]. This goes to suggest that THC can help inhibit neurodegenerative conditions, like Alzheimer’s, Parkinson’s, Huntington’s Diseases. Smoking marijuana has also been seen to increase cerebral blood flow immediately, a process that continues for about 2 hours after use [13, 14]
  4. Stimulates appetite: An oft-observed after-effect of smoking marijuana is an increase in appetite. THC has been scientifically proven to stimulate appetite [15] as well as metabolism. This may help people suffering from eating disorders, especially those suffering from lack of appetite. 
  5. Hinders heart disease: THC can effectively fight cholesterol [16] by inhibiting the hardening of blood vessels.  
  6. Prevents cancer by inhibiting tumor growth: In the case of brain cancer, THC, when directly injected into the glioblastoma tumors, can inhibit growth and multiplication of tumor cells, thus increasing life expectancy by around 24 weeks [17]. Another study found evidence of CBD enhancing this effect [18]. In certain cases, THC can also be effective in combatting breast cancer [19], lung cancer [20], and also prostate cancer [21]
  7. Induces deep sleep: Cannabinoids, especially psychoactive ones like THC, seems to decrease the time taken to fall asleep as well as increase the length of Stage 4 sleep while decreasing REM sleep [22].
  8. Prevents seizures: THC has been found to stop epilepsy-related seizures among rats [23]
  9. Increases Insulin Sensitivity: THC tends to reduce fasting insulin levels. Studies found that current marijuana users experienced a 16% lowering of insulin levels compared to past users and a 26% lowering compared to those who have never used marijuana [24].  

THC for your dog? Can it kill my pet?

If a dog accidentally eats marijuana or food laced with it, he will definitely get high. A little more can turn toxic (neurologic toxicity, known as Static Ataxia). However, if he ingests too much, there is a certain amount of risk that he may also die. 

Even if he doesn’t die, suffering from ataxia is dangerous enough. Ataxia is associated with sensory dysfunction that leads to loss of coordination of the limbs, head, and/or body. It is exhibited by staggering, agitation, stupor, etc. This experience is by no means enjoyable or pleasurable for animals. For them, it’s simply a very scary feeling.

An animal can die from this toxicity due to anyone or a combination of these effects, including rapid or fluctuating high and low heart rate, extremely low pressure, unusual vomiting, disorientation, unbalanced movements, and accidental crashing into objects. 

Nonetheless, the extent of the effects depends on the age, health status, and body size of your dog. 

Adverse effects of THC on your dog

Ironically, dogs have the highest concentration of CB1 receptors – the endocannabinoids receptor that binds with THC – particularly in the areas of their brain that controls coordination and motor movements. It’s no wonder that the effects of THC are far more severe in cases of dogs than other mammals. If your canine companion accidentally chows down your weed stash, he or she will start experiencing its psychedelic effects around 30 to 60 minutes after ingestion. 

Some of the more general effects include:

  • Difficulty walking
  • Stumbling, staggering, dragging paws, wobbly movements 
  • Twitching/trembling/shaking 
  • Disorientation, Rocking back and forth on the spot
  • Drooling 
  • Wide-open eyes 
  • Tense muscles & edgy, nervous reactions
  • Paranoia, indicated by panting, pacing and other forms of hyperactivity 
  • Unusual whining 

All of these effects, or symptoms, are caused by total loss of control over the dog’s voluntary muscles, and a combination of these symptoms is called Ataxia.

What’s even worse is that dogs metabolize cannabinoids much slower than humans do. This means that THC’s effects persist for up to 24 – 36 hours or even longer. According to some studies, 3 grams of oral THC per kg of body weight is a lethal enough dose for dogs [25]

Dogs may also experience some more intense, and sometimes harsher, effects like: 

  • Lethargy
  • Severe depression
  • Dilated pupils and glassy eyes
  • Vomiting
  • Erratic breathing and breathlessness
  • Low blood temperature
  • Low or high heart rate, fluctuating heart rate
  • Low blood pressure 
  • Unusually loud and erratic whining & crying
  • Loss of bladder control (incontinence)
  • Seizures/tremors or even coma (rare and extreme cases)

The intensity and extent of effects depend on the size and age of the canine. Smaller dogs and pups tend to get more “high” after consuming a certain amount of marijuana than an adult dog or one with higher body weight. 

As far as clinical trials on cannabis use by dogs are concerned, only two studies have been conducted since 2016 [26]. However, they were on CBD use on dogs, and not of THC, as it is not considered safe for canines. 

Can your pet get “high” on second-hand marijuana smoke?

Possibly yes, but not if you keep all the windows open, allowing all the smoke to leave the room quickly enough. 

Dogs have extremely sensitive lungs, and smoke can damage them. A dog’s respiratory function can be compromised leading to even death [28]

It is safest to refrain from smoking marijuana or even cigarettes in an enclosed room with your dog inside on a regular basis. Either send him outside the room or keep a large window or a door open – or simply don’t smoke too often – that is if you don’t want your dog to die of pulmonary issues [29]

When’s it time to call the Vet & what can we expect?

Weed is indeed the Devil for dogs. The Pet Poison Helpline [27] warns pet owners that the risk of cannabis poisoning among dogs is moderate to severe. In fact, the ingestion of a large amount of marijuana can kill your pet. In case your dog accidentally ingests marijuana or (if he does so behind your back) if you notice the side effects we discussed earlier, you should immediately rush him to your nearest veterinarian or call the Animal Poison Control.

Pet owners often refuse to take their dog to the vet after their pet suffers from marijuana poisoning for fear of legal consequences. However, one must not fear. No legal action is taken in such cases. On the other hand, if you do not take your pet to the doctor when he has accidentally consumed marijuana, you may have to suffer the consequence of watching your beloved pet die. 

If you’re honest with the vet about what led to the sudden adverse reactions, the doctor can start the treatment without easting any time on diagnostic tests. 

If you have noticed your pet dog consume marijuana, rush him to the vet. If attended within a couple of hours, the vet can induce vomiting to remove it from his system. However, if the marijuana is already absorbed into the system and/or your dog is already exhibiting the symptoms (mentioned earlier), then it is too late to induce vomiting. 

Your vet’s next course of action will be to provide supportive care. He will put your pet on intravenous fluids to dilute the toxins and decrease their rate of absorption. In severe cases, your vet will advise you to admit your pet to the hospital, where he will be put on IV lipid or fat to absorb or trap the THC. He may also be needed to be put on oxygen support in case of respiratory problems due to inhalation of vomit or inability to vomit. In such cases, you need to be mentally prepared that your dog may not survive the ordeal. 

Effects of giving products containing both CBD & THC to dogs

Then, what about medical marijuana? While medical marijuana has been seen to provide dogs with relief for arthritis and cancer and even fought nausea and increased appetite in some case, it is still not approved by the AVMA, ASPCA or other animal activist organizations. 

Owing to the lack of adequate research in this area, it is not advised to administer THC to your dogs. 

Unlike THC, however, CBD has been found to be comparatively safe and effective for dogs. 

In fact, CBD has one of the safest side-effect profiles and has quite a few health benefits. Its side effects in dogs are also very few as they are mild. However, you must remember that dogs need and can tolerate cannabinoids much less than humans. 

The worst that can happen to your dog after using CBD is lethargy and diarrhea. However, the health benefits far exceed those of THC. 

CBD is Healthier, Safer & More Effective Alternative for Dogs

And it is also legal

CBD has many therapeutic benefits that work quite safely on the body, no matter which species of mammal may be using it. 

For your canine companion, CBD oil is not only therapeutic, but it is also quite safe and effective. 

There are times when we wish there could be something other than conventional medicines that could provide better relief and comfort to our beloved fur babies. However, marijuana or THC can actually do more harm than good. 

CBD has been scientifically proven to have lower toxicity and higher tolerability than THC among all mammals. It is much safer and more effective to give your pet CBD isolates that do not have any THC than full-spectrum CBD products, medicinal marijuana or regular marijuana. 

In order to alleviate your pet’s pain and suffering, it is safest and most effective to administer him or her with CBD for pets than marijuana. This will ensure your dog heals faster and lives a long and healthy life. 


Research citations:

  1. Cannabinoids in the management of difficult to treat pain; Therapeutics & Clinical Risk Management; February 2008; Ethan B Russo; 
  2. Cannabis and Pain: A Clinical Review; Cannabis and Cannabinoid Research; May 1, 2017. Kevin P Hill, Matthew D Palastro, Brian Johnson, and Joseph W Ditre; 
  3. Cannabinoids for treatment of chronic non-cancer pain; a systematic review of randomized trials; British Journal of Clinical Pharmacology; November 2011; Mary E Lynch and Fiona Campbell;
  4. The Consumption of Cannabis by Fibromyalgia Patients in Israel; Pain Research & Treatment; July 22, 2018; George Habib and Irit Avisar;
  5. Regulation of nausea and vomiting by cannabinoids and the endocannabinoid system; European Journal of Pharmacology; November 1, 2013; Keith A Sharkey, Nissar A Darmani, and Linda A Parker; 
  6. Dronabinol for chemotherapy-induced nausea and vomiting unresponsive to antiemetics; Cancer Management & Research; May 12, 2016; Megan Brafford May and Ashley E Glode; 
  7. Delta9-tetrahydrocannabinol and endogenous cannabinoid anandamide directly potentiate the function of glycine receptors; Molecular Pharmacology; December 6, 2005; Hejazi N, Zhou C, Oz M, Sun H, Ye JH, Zhang L; 
  8. Agmatine and a cannabinoid agonist, WIN 55212-2, interact to produce a hypothermic synergy; European Journal of Pharmacology; August 26, 2006; Rawls SM, Tallarida RJ, Zisk J; 
  9. Cannabinoids for treatment of spasticity and other symptoms related to multiple sclerosis (CAMS study): multicentre randomised placebo-controlled trial; Lancet; November 8, 2003; Zajicek J, Fox P, Sanders H, Wright D, Vickery J, Nunn A, Thompson A; UK MS Research Group; 
  10. Cannabinoids in multiple sclerosis (CAMS) study: safety and efficacy data for 12 months follow up; Journal of Neurology & Neurosurgical Psychiatry; December 2005; Zajicek JP, Sanders HP, Wright DE, Vickery PJ, Ingram WM, Reilly SM, Nunn AJ, Teare LJ, Fox PJ, Thompson AJ; 
  11. A pilot study of the effects of cannabis on appetite hormones in HIV-infected adult men; Brain Research; November 7, 2011; Riggs PK, Vaida F, Rossi SS, Sorkin LS, Gouaux B, Grant I, Ellis RJ; 
  12. Changes in the expression of G protein-coupled receptor kinases and beta-arrestins in mouse brain during cannabinoid tolerance: a role for RAS-ERK cascade; Molecular Neurobiology; June 2006; Rubino T, Viganò D, Premoli F, Castiglioni C, Bianchessi S, Zippel R, Parolaro D; 
  13. Acute changes in cerebral blood flow after smoking marijuana; Life Sciences; 1993; Mathew RJ, Wilson WH; 
  14. Regional cerebral blood flow after marijuana smoking; Journal of Cerebral Blood Flow Metabolism; September 1992; Mathew RJ, Wilson WH, Humphreys DF, Lowe JV, Wiethe KE; 
  15. Cannabinoids and appetite: food craving and food pleasure; International Review of Psychiatry; April 2009; Kirkham TC;
  16. Cannabinoid receptors in acute and chronic complications of atherosclerosis; British Journal of Pharmacology; January 29, 2009; F Mach  F Montecucco S Steffens;
  17. A pilot clinical study of Delta9-tetrahydrocannabinol in patients with recurrent glioblastoma multiforme; British Journal of Cancer; June 27, 2006; Guzmán M, Duarte MJ, Blázquez C, Ravina J, Rosa MC, Galve-Roperh I, Sánchez C, Velasco G, González-Feria L; 
  18. Cannabidiol enhances the inhibitory effects of Δ9-tetrahydrocannabinol on human glioblastoma cell proliferation and survival; Molecular Cancer Therapy; January 6, 2010; Jahan P Marcu, Rigel T Christian, Darryl Lau, Anne J Zielinski, Maxx P Horowitz, Jasmine Lee, Arash Pakdel, Juanita Allison, Chandani Limbad, Dan H. Moore, Garret L Yount, Pierre-Yves Desprez, and Sean D McAllister;
  19. Cannabinoids reduce ErbB2-driven breast cancer progression through Akt inhibition; Molecular Cancer; July 22, 2010; Caffarel MM1, Andradas C, Mira E, Pérez-Gómez E, Cerutti C, Moreno-Bueno G, Flores JM, García-Real I, Palacios J, Mañes S, Guzmán M, Sánchez C; 
  20. Delta9-Tetrahydrocannabinol inhibits epithelial growth factor-induced lung cancer cell migration in vitro as well as its growth and metastasis in vivo; Oncogene; July 9, 2007; Preet A, Ganju RK, Groopman JE; 
  21. The endocannabinoid system in prostate cancer; Nature Reviews Urology; September 13, 2011; Díaz-Laviada I; 
  22. Effect of illicit recreational drugs upon sleep: cocaine, ecstasy and marijuana; Sleep Medicine Reviews; March 3, 2008; Schierenbeck T, Riemann D, Berger M, Hornyak M; 
  23. The endogenous cannabinoid system regulates seizure frequency and duration in a model of temporal lobe epilepsy;  Journal of Pharmacology and Experimental Therapeutics; September 3, 2003; Wallace MJ, Blair RE, Falenski KW, Martin BR, DeLorenzo RJ;
  24. The Impact of Marijuana Use on Glucose, Insulin, and Insulin Resistance among US Adults; The American Journal of Medicine; Elizabeth A Penner, MD, MPH, Hannah Buettner, BA, Murray A Mittleman, MD, DrPH; July 2013; 
  25. Marijuana poisoning; Topics in Companion Animal Medicine; February 2013; Fitzgerald KT, Bronstein AC, Newquist KL; 2013 
  26. Cannabis research for veterinary patients advancing, cautiously: Hemp provision in 2014 Farm Bill seen as opening the way for research; Journal of American Veterinary Medical Association; July 11, 2018; R Scott Nolen; 
  27. Pet Poison Helpline; Marijuana; 
  28. Chronic inhalation of marijuana and tobacco in dogs: pulmonary pathology; Res Commun Chem Pathol Pharmacol. 1976 June; Roy PE, Magnan-Lapointe F, Huy ND, Boutet M.
  29. Cannabis smoking and lung cancer risk: Pooled analysis in the International Lung Cancer Consortium; International Journal of Cancer; June 30, 2014; Zhang LR, Morgenstern H, Greenland S, Chang SC, Lazarus P, Teare MD, Woll PJ, Orlow I, Cox B; Cannabis and Respiratory Disease Research Group of New Zealand, Brhane Y, Liu G, Hung RJ; 
Author Details
Senior Editor & Researcher , Greenthevoteok
Matt Hansel is a Medical Practitioner, who has been writing and researching about cannabis since 2014.  His popular quotes which we like are: \"Don\'t use CBD oil for a cure, use it as a precaution\"  \"CBD should be considered as any other vitamin supplement and your body needs it!\"