Case Study Shows Potential Danger of Contaminated Cannabis | Marijuana

Case Study Shows Potential Danger of Contaminated Cannabis


A recent study points to fungus-infested cannabis as the cause of Valley Fever in a California female, according to an article originally published in the British Daily Mail. The January study cited consumption of outdoor cannabis that contained Coccidioides Immitis fungus as the source of the infection.

According to a case study published in January’s British Medical Journal, a 48-year-old woman and cannabis patient who smoked up to six blunts a day had been suffering from dizziness, tiredness, could not remember her name and was behaving aggressively. After a few weeks, the doctors identified a coccidioidomycosis infection as the cause, but it was unclear how the patient had become infected.

In some regions of California, the fungus Coccidioides Immitis is present in the soil. This fungus species can cause Coccidioidomycosis, commonly known as Cocci, Valley fever, California fever or desert rheumatism, in humans. When plants are cultivated in soil where this fungus is present, the spores inevitably end up on the plant.

To confirm their suspicion, the researchers took samples from the patient’s dispensary in Bakersfield. More than 90 percent of the marijuana plants tested were contaminated with pesticides, and crops from 20 farms were tested positive for mold.

In most of the women’s preferred outdoor strains, researchers found Coccidioides Immitis spores in three out of nine samples. Researchers also found instances of  Cryptococcus neofarns. The investigating doctors said it is possible that fungal spores can survive the burning that occurs when patients smoke the herb.

This is not the first time concerns of mold and other contaminants have been raised, but until this case, it was suspected that only people with a suppressed immune system could be infected by smoking fungus-contaminated medical cannabis. This is the first documented case of a person with an intact immune system being infected by inhaling cannabis contaminated with Coccidioides Immitis.

Asked about the consequences for patients, the woman’s treating MD and conductor of the study, Dr. Bryan Sharpiro told the Daily Mail.

“Make sure you know where your marijuana is coming from. I recommend buying indoor-grown strains and, for people who are immuno-compromised like those with HIV or other infections, I would recommend avoiding inhaled marijuana products. Edible products, on the other hand, are probably safer for consumption.”

How do I know if my cannabis is contaminated?

Many US states with medical marijuana laws have lab analysis requirements in place to ensure the product being served to the patients is free of contaminants, including pesticides, mold and other residual products. California’s recreational rollout this year included lab testing requirements that were not heavily enforced prior to legalization.

Whether or not a state requires a lab test, verifying the cleanliness of medicinal cannabis is important to patient health.

Bonni Goldstein, M.D. is a published author and physician who specializes in cannabis medicine in Los Angeles. In her professional opinion, the dangers these products pose to consumers and the industry is significant.

“Patients who are already struggling with serious medical conditions don’t need additional issues with their medicine,” Goldstein told in a previous interview. “They shouldn’t have to worry that the products they use are counterfeit or contaminated. Dispensaries are in the business of helping medical patients find the medicine that will help them and it’s incumbent on them to screen for counterfeit products and only offer quality tested products.”

About Author

Michael Knodt is an expert on cannabis politics and cannabis culture across Europe. Born in North Germany, Michael has been living in Berlin since 1990. He initially studied history and journalism before receiving his certification as a carpenter. Since then, Michael has made regular visits to countries where cannabis is cultivated, such as Jamaica and Morocco. He has worked as a freelancer for Weedmaps, Vice Magazine Germany, Sensi Seeds and numerous German-language cannabis magazines since 2004. From 2005 to 2013, Michael was the Editor-in-Chief of Germanys biggest cannabis periodical. He also is the face and presenter of the most popular program on cannabis prohibition and just launched a new channel called "DerMicha." Aside from his journalistic work, Michael is a cannabis patient, activist, sought-after speaker on conferences and congresses, and a father of two.


  1. Dang! That’s bad news. People still don’t know how to grow Cannabis. It takes a special kind of stupid to smoke weed that’s contaminated. Trust your sources or GYOB.

  2. State regulators will have to treat testing and monitoring much more serious than this. The state, is in essence, telling consumers, through legalization, that this product is safe for state sponsored consumption. If they have to close a grow op, so be it. All participants should understand the rules of safety to operate, or suffer the consequences. Plain and simple. I’m sure there are plenty of virtuous folks just waiting to get involved in the industry and play by the rules. There is no excuse for this sort of sloppiness.

  3. self-evidently, consumer products must be tested for pesticides, toxins, or any potential threat to human health..
    this requirement supports, rational well managed cannabis cultivation and sale..
    blackmarket cannabis could be, from a boutique specialist grower who cares,
    or it could be from some unknown source which runs on profit above all else..

    legal cannabis should be well managed with strong oversight such as canadas
    soon to be available for public sale govt controlled recreational cannabis..

    bear in mind tho the millions of regular cannabis users who have had zero
    negative pollution effects in lifetimes of cannabis use..
    pollution, pesticides, etc, are manmade unnatural additives to,
    this non-addicting, nontoxic, therapeutic; god given natural herb..

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