Ask a Vet: How Can I Tell Whether My Dog Ate Marijuana?

Dr Barchas, I am very concerned about my 1-year-old Boston Terrier. Last Monday he was playing and romping as he always does; he came in...


Dr Barchas,

I am very concerned about my 1-year-old Boston Terrier. Last Monday he was playing and romping as he always does; he came in for a nap and went directly into a deep sleep. Two to two and a half hours passed and I woke him for dinner. He was very lazy and droopy-eyed, and very slowly came in the kitchen to eat. He put his head in the bowl and then fell back on his rear. He was completely out of it.

My ex-husband spends some time at my house and made a comment about Pinky possibly getting a roach part of a joint he had put on a table on my outside patio. panicked and ran the dog to the emergency clinic.

He was so out of it he could barely stand up for up the next three hours. The vet did two complete drug screens — urine and blood tests galore. All came back negative. Nothing out of range on any of the tests!! After two vets running tests and spending $1,000, I still have no diagnosis for my kid. He seems fine now; they kept him two nights and days and gave him IV fluids, plus charcoal to absorb anything in his system.

I’m at a loss and don’t feel comfortable about the entire thing!!! Can you help?


Your dog certainly seems to have suffered from an episode of intoxication. Given the symptoms you describe, and the fact that your ex-husband pretty much copped to it, I’m strongly suspicious of marijuana intoxication. I say this despite the two negative drug tests (more on drug testing in a moment).

The background and symptoms you describe fit marijuana ingestion perfectly. A typical case looks like this: An otherwise healthy dog suddenly becomes visibly lethargic and disoriented and may have trouble walking. The dog may (or may not) dribble urine. The dog may overreact to tactile, auditory, or visual stimuli. All vital signs will be normal. Gum coloration (a sign of circulation) will be normal. Pulses, blood pressure, and bloodwork will be normal. The dog should recover fully within 24 to 48 hours, depending upon the quantity of marijuana ingested.

There is good news about marijuana ingestion.

First, there essentially is no fatal dose, as long as you can avoid complications such as dehydration or vomiting with aspiration (inhalation) of the vomit. I have seen dogs survive after eating pounds of high-potency Humboldt buds. I have treated hundreds of known or suspected cases of marijuana ingestion, and not one of these patients has died — or even suffered any real complications. They generally do require veterinary treatment, but with treatment the prognosis is excellent.

Second, once dogs recover from marijuana ingestion, they recover fully. There are no long-term effects. This means that if marijuana did cause your dog’s symptoms, there should be no problems moving forward — as long as no more exposures occur.

As for your dog’s negative drug screens — veterinarians generally employ standard human urine drug test kits that are generally highly accurate for most drugs, although they have two flaws. First, certain medications can cause false positives for drugs such as amphetamines. Second, and more important in your case, false negatives are common for marijuana.

Marijuana often takes a few days to show up in urine drug screens, so many dogs that have consumed marijuana will test negative at the time of treatment. I suspect that’s what happened with your dog. However, marijuana metabolites are notorious for staying in the body for a long time — up to six weeks.

If you really want to know what happened to your dog, you could try drug-testing him now. Your vet should be able to run the test, or you could do it yourself. The tests are available at drugstores.

If your dog tests positive, you have your answer. If not, remember that false negatives still are possible. Marijuana may or may not be the culprit in the event of a negative result. Either way, however, I am very optimistic about your dog’s future.

7 thoughts on “Ask a Vet: How Can I Tell Whether My Dog Ate Marijuana?”

  1. I’m not sure my dog ate pot but when we took him to the vet she seemed 100% certain from his symptoms that’s what he did..he went outside so unless the shed head tossed it in my yard Idk she stated that it didn’t seem like it was a lot being she’s seen worse cases.. so do they slowing start to get better or is it bam their better.. Sam has like 4 hours left in his 24 hours but he’s not better he still can’t walk.. l

  2. My dog is only 4 lbs and he ate a nug of weed he’s been wobbly while walking falling a lot today doesn’t really want to eat or drink anything I’ve been giving him water and pidialyte threw a sirenge I’m so scared he will die what should I do I can’t afford the vet

    1. Hi Mary,
      Please get your dog to the vet ASAP. Here are some articles that might offer some insight:

  3. My dog ate marijuana yesterday and he was felling all over the place and couldn’t, but he slept all night, and this morning I gave him water, but now he’s not eating his food, will he be ok?

  4. You really make it seem really easy along with your presentation however I to find this matter to be actually something which I believe I might never understand.

    It kind of feels too complicated and very extensive for
    me. I am looking ahead in your next submit, I’ll attempt to get the dangle of it!

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