The truth about secondhand cannabis smoke: Can you really get a contact high?

The truth about secondhand cannabis smoke: Can you really get a contact high?

By now, someone has probably tried telling you that you can get high from secondhand smoke. You've also likely heard that it can't. So which one is it? And what effect does it have on you passing a drug test? Whether you have kids at home or must stay clean for work or court, it's certainly important to know the answers to these two questions.


It's no secret that a frequently debated topic about cannabis is the contact high. After sitting in a room full of weed smoke, you might find that your eyes are as red as a cherry and you'll probably even feel tired. But are these symptoms of a secondhand high? Not likely.

As you take a hit, most of the THC, the psychoactive component of cannabis, is absorbed before you exhale. Is there a chance that you can catch a slight buzz if someone blows the smoke directly into your mouth? Yes. However, being surrounded by a bunch of pot smokers likely won't get you stoned.

In fact, it's next to impossible to get a contact high. According to Cecilia J. Hillard, who's both a pharmacology professor and the director of the Neuroscience Research Center at the Medical College of Wisconsin, the lungs are great at capturing the THC in cannabis.[1] And when a person releases the smoke into the air, very little of the THC is present.


In 2010, the Journal of Analytic Toxicology conducted a study that also concluded the difficulty of getting high off secondhand smoke.[2] While it can leave traces of THC in your system, it's nowhere near enough to actually get you stoned.

On the other hand, the study did discover that there is a way to get a contact high, but only if you go to the extreme. After subjects had spent an hour in a small room with 16 joints being passed around and clouding the room with massive amounts of smoke, they were able to get just as high as they would if they smoked alone.

Does this mean secondhand smoke exposure can cause you to fail a drug test? It's possible, but highly unlikely. If this is a concern for you, just drink plenty of water and exercise regularly. It shouldn't take much work to burn off what little THC might have made its way into your system.


To sum it all up, yes, there is a slim chance that you can catch a small buzz off second-hand cannabis smoke. But more than likely, it's all in your head and whatever symptoms you're experiencing are just due to being surrounded by too much smoke.

As for passing a drug test, you should have no issues. Unless of course, you lock yourself in a small space for hours with heavy amounts of weed smoke. And even if you do, again, only tiny traces of THC will find its way into your system, if any at all. In that case, all you need to do is hydrate and stay active.

In case you're still not convinced that you'll be fine, the solution is simple. Don't partake in a hotbox session unless you plan on puffing.


  1. ^ Business Insider, Can You Really Get a contact high from marijuana?, retrieved December-12-2018
  2. ^ NCBI, Non-smoker exposure to secondhand cannabis smoke. I. Urine screening and confirmation results, retrieved December-12-2018