Do you know what's in your weed?
La Presse had tests done on samples of marijuana sold on the streets and pot issued by licensed medical marijuana producers.
While the latter didn't show any problems, the illicit marijuana did not fare well.
The tests ordered by La Presse showed high concentrations of a particular pesticide in the street marijuana that if inhaled in major regular doses can cause fatal heart attacks; long term exposure can cause instability in the nervous system and thyroid gland problems.
Samples from Montreal's Compassion Club showed high levels of a bacteria harmful to humans with weakened immune systems.
Owner Marc-Boris St-Maurice said they no longer offer that lower-grade variety which came from a batch grown outdoors - subject to unpredictable weather conditions and foreign organisms.
"It's pretty much the lowest quality that we offer on the menu," said St.-Maurice.
"That's why we're concerned that the sample not be taken as indicative of the entirety of our inventory here."
St-Maurice said in general they don't have issues with quality.
"We do steer our customers towards a higher quality product when possible and we're going to make sure we test everything to reassure everyone," said St-Maurice in an interview with CJAD 800 News.
St-Maurice said the street pot results are cause for concern and that people should be cautious when buying but added that in general, "the use of pot in the past 50 years available in the illicit market has a relatively safe margin" for the majority of users.