Medical researchers at UC Davis are urging some medicinal pot users to stop smoking or vaping the drug to avoid risk of lung infection.
The warning comes after researchers found high instances of invasive fungal infections in leukemia and lymphoma patients.
"And the commonality for those patients was that all of them were using medical marijuana," says microbiology professor George Thompson. He explains that bacteria and mold on cannabis can be potentially lethal to people with weakened immune systems who smoke pot to help control nausea. Those patients are typically told to avoid other things that can harbor bacteria like cut flowers and unwashed fruits or vegetables.
"Just like medical marijuana, they're decaying vegetated materials so they're covered in mold and bacteria. They're told not to have cut flowers when they're in their hospital room for the same reason. They're told to avoid bath toys because they contain bacteria in the water when it's sort of retained inside those. So there's really a long list of things these patients [are] told to avoid."
Thompson says marijuana belongs in that group.
Patients are "directly inhaling it into their lungs. So you're sort of bypassing most of your direct barriers," says Thompson. "You know, your skin is a significant barrier to infection. But inhaling something that's just covered in microbes really puts people at a high risk for invasive infections."
Researchers found bacteria and mold on 20 cannabis samples obtained from Northern California dispensaries.
Thompson says it's unknown if eating marijuana in baked goods is safe. But he says for patients who want to use the drug, that it is probably a better option.
The risk of infection is low for the majority of medical marijuana users.