Marijuana (Cannabis sativa) is also known by the street names grass, pot, weed, and Mary Jane. It’s the most popular illegal drug in the world and in the United States and may cost up to $6,000 per pound. Often, pets are exposed by ingesting baked goods such as brownies or cookies that contain marijuana. Occasionally, pets ingest the dried plant or are intentionally exposed by people blowing smoke into their faces.
Unfortunately, human urine drug tests do not work well for screening dogs for marijuana toxicity, as they often falsely test negative. And these tests haven’t been closely evaluated in cats. For more information about drug testing for dogs, click here.
The signs of marijuana intoxication are similar to those seen in people and begin 30 to 60 minutes after ingestion; however, they may last much longer in dogs and cats—many take 18 to 36 hours to recover. The most common signs are depression, a glassy-eyed appearance, stumbling, dilated pupils, vomiting, and, in about 25 percent of dogs, agitation and excitement. Serious effects include changes in heart rate, tremors, and seizures. Thankfully, marijuana has a wide margin of safety, and death from toxicity is not common.