Symptoms of Marijuana Poisoning in Dogs
Stumbling and crossing over feet
Dull and lethargic
Dilated pupils
Urinary incontinence
Vomiting
Tremors and shaking
Agitation
Tetrahydrocannabinol (THC) is the potent psychoactive substance in marijuana, and dogs have a much more severe reaction to this than humans. Symptoms are typically visible within 30 minutes to an hour after ingestion of the drug, or sooner if inhaled.

Dr. Stacy Meola is a criticalist at Wheat Ridge Animal Hospital in Colorado and was also one of the lead veterinarians involved in the previously-mentioned study. She explains that “the most common sign is stumbling and crossing over their feet, and walking like they are drunk (ataxic).” In the study, 88% of the dogs presented with this symptom. Around 50% of dogs will also likely appear dull and lethargic with dilated pupils, and will flinch in reaction to fast movements toward their face.

“The most interesting sign in dogs is urinary incontinence,” says Dr. Meola, adding that around half of the dogs studied dribbled urine uncontrollably when they had marijuana in their system. “My guess is the drug would not be as popular if 50% of people dribbled urine when they used marijuana!”

Other possible symptoms include vomiting, tremors and shaking, and agitation, and some dogs can become comatose.