Some mushroom species and mushroom compounds, especially beta-glucans and cordyceps extracts, have been studied for their effects on immune defense and lung-related outcomes. Human trials show modest, mixed benefits for things like fewer cold symptoms and some lung function measures in people with existing lung disease. These results come from a limited number of studies, so they describe possible support, not a treatment or support for any respiratory condition.
This article separates what has been tested in people from what has only been tested in cells or animals, so you can weigh the evidence accurately before making any decisions.
When to Get Emergency Help First
No mushroom product treats a breathing emergency. Get emergency medical care right away for any of these signs:
- Trouble breathing or shortness of breath that is severe or getting worse
- Chest pain or tightness
- Blue or gray color around the lips, face, or fingertips
- Confusion, extreme drowsiness, or fainting
- Coughing up blood
- A known severe allergic reaction (swelling of the face or throat, wheezing, hives with breathing trouble)
None of the mushroom research described below applies to emergencies like these. Call your local emergency number or go to an emergency room.
How Mushrooms May Support Immune and Respiratory Function
Mushrooms contain compounds such as beta-glucans, a type of fiber found in the cell walls of fungi, along with other polysaccharides and antioxidants. Researchers believe these compounds may interact with immune cells in ways that could support the body’s defenses, including its response to upper respiratory infections. This is an area of active research, and scientists are still working out which compounds matter most, at what amounts, and for whom.
The National Cancer Institute (NCI), part of the National Institutes of Health, notes that mushroom extracts such as turkey tail (PSK) and reishi have been studied in cancer settings partly because of their effects on immune cells called natural killer cells and T-cells. That research is specific to cancer care and does not establish general respiratory benefits, but it is a useful example of how mushroom compounds are believed to interact with the immune system.
Separating Human Evidence From Animal and Lab Evidence
Respiratory and immune research on mushrooms spans several evidence types. Not all of them tell you the same thing about what happens in a living person.
- Human clinical trials: People take a mushroom extract or a placebo, and researchers measure outcomes like infection symptoms or lung function tests. This is the most relevant evidence for a person deciding what to do, but even here, results vary by species, dose, and study quality.
- Human observational or pattern studies: Researchers look at groups of people who already eat or use mushrooms and compare health outcomes. These studies can show a pattern, but they cannot prove the mushrooms caused the result.
- Animal studies: Mice or rats are given mushroom extracts, often at doses or forms not tested in people. These studies help explain possible mechanisms but do not confirm the same effect happens in humans.
- Cell (in-vitro) studies: Mushroom compounds are tested on cells in a lab dish. This is the earliest, least direct type of evidence for how a mushroom might affect a person’s lungs or immune system.
For a full walkthrough of how to weigh these evidence types, see this site’s evidence hierarchy guide.
Human Clinical Evidence: Beta-Glucans and Upper Respiratory Infections
The strongest human evidence in this area comes from beta-glucans, which are found in mushrooms as well as in baker’s yeast. A 2021 systematic review published in the journal Food & Function analyzed 34 randomized controlled trials of oral beta-glucan supplementation, including trials that used mushroom sources such as oyster mushroom, shiitake, and reishi.
Across that body of research, the review reported that 17 of the trials found beta-glucan supplementation was associated with fewer upper respiratory infection symptoms, shorter symptom duration, or fewer symptomatic days in groups that included healthy adults, children with recurrent infections, older adults, and athletes. Some trials also found changes in immune markers, such as preserved natural killer cell activity during intense exercise or increased salivary IgA, a marker of mucosal immune defense, though results for these markers were inconsistent across studies.
The review’s authors were careful about the limits of this evidence. They noted the trials were too different from one another in dose, mushroom or yeast source, and study length to combine into a single statistical estimate. Only 3 of the 34 trials followed participants after supplementation ended, and most trials did not track participants’ overall diet, which can also affect immune function. The authors concluded that beta-glucan supplementation appeared well tolerated with no adverse events linked to it, and that more standardized research is needed to confirm effects and identify an optimal dose.
Human Clinical Evidence: Cordyceps and Lung Function in COPD
Cordyceps is a fungus used in traditional Chinese medicine and has been studied as an add-on therapy for people with chronic obstructive pulmonary disease (COPD), a long-term lung condition. A 2019 systematic review and meta-analysis published in Evidence-Based Complementary and Alternative Medicine looked at oral Cordyceps sinensis used alongside standard COPD medication in people with stable, moderate-to-severe (GOLD stage 2–3) COPD.
According to that review, combining Cordyceps sinensis with standard treatment was associated with improvement in lung function measurements, including FEV1 (the amount of air a person can force out of their lungs in one second) as a percentage of the predicted value, and the FEV1/FVC ratio, compared with standard treatment alone. A more recent randomized trial has also tested Cordyceps militaris capsules against acute flare-ups in COPD, though that trial did not use a placebo group and used flare-up events rather than a lung function test as its main measure, which limits how confidently its results can be interpreted.
This research describes an add-on approach studied in people who already had diagnosed, stable COPD and were already using standard medical treatment. It does not show that Cordyceps prevents COPD, reverses lung damage, or works as a substitute for prescribed inhalers, oxygen therapy, or other treatment a lung specialist recommends.
Species Snapshot: What Has Been Studied and How
- Beta-glucans (multiple mushroom species): Studied in 34 randomized controlled trials (systematic review) for upper respiratory infection symptoms and immune markers. Key limitation: trials were too varied to combine into one estimate, and most had short follow-up.
- Cordyceps sinensis: Studied in a systematic review and meta-analysis of add-on trials for lung function (FEV1, FEV1/FVC) in stable COPD. Key limitation: used alongside standard treatment, not tested alone, and individual trial quality varies.
- Cordyceps militaris: Studied in one recent randomized trial (no placebo group) for COPD flare-up events. Key limitation: no placebo comparison, and flare-ups were used instead of a lung function test.
- Reishi (Ganoderma lucidum) and turkey tail (PSK): Studied in clinical trials mainly in cancer care settings for immune cell activity (natural killer cells, T-cells). Key limitation: findings are specific to cancer treatment contexts, not general lung health.
For background on individual species, including how they are traditionally prepared and used, see this site’s mushroom species guide.
A Simple Decision Path Before Trying a Mushroom Product
- Step 1: Do you have a diagnosed lung or breathing condition? If yes, talk with the clinician managing that condition before adding any mushroom supplement. Mushroom products are not a substitute for prescribed COPD, asthma, or other respiratory treatment.
- Step 2: Are you taking prescription medication, especially blood thinners or immune-suppressing drugs? Some mushroom compounds may interact with these. Ask a pharmacist or your prescribing clinician before starting a supplement.
- Step 3: Do you have a mushroom, mold, or fungal allergy? Avoid mushroom supplements if so, and watch for allergic reaction symptoms with any new product.
- Step 4: Are you pregnant, breastfeeding, or considering a supplement for a child? Ask a clinician first, since most of the trials described above involved specific adult populations.
- Step 5: If none of the above applies, and you still want to learn more, review the safety and interaction information below and read product labels carefully, since mushroom supplements are not tested or approved by the FDA the way medications are.
Extra-Caution Groups
The research above generally excluded or did not focus on these groups, so extra caution and medical guidance apply:
- People with diagnosed COPD, asthma, or other chronic lung disease who are on prescribed treatment plans
- People taking anticoagulant (blood-thinning) medication, since some mushroom compounds may affect clotting
- People with autoimmune conditions or taking immunosuppressant medication, since immune-modulating compounds could interact with these conditions or drugs
- People with a known mushroom, mold, or fungal allergy
- People who are pregnant or breastfeeding
- People scheduled for surgery, since some supplements can affect bleeding or interact with anesthesia
Evidence Limits
Readers should understand what this research does and does not show:
- Most respiratory-related human trials studied mushroom compounds as an add-on to standard treatment, not as a stand-alone solution.
- Study sizes, doses, mushroom sources, and lengths varied enough that researchers could not combine many of these trials into one statistical conclusion.
- No study reviewed here shows that a mushroom product prevents a respiratory infection, supports a lung condition, or replaces prescribed medical treatment.
- Much of the mechanistic explanation for how mushroom compounds might affect the lungs comes from animal or cell studies, which do not commitment the same effect in people.
- Mushroom supplements sold to consumers are regulated as dietary supplements, not drugs, so they are not required to prove effectiveness before being sold.
For more on how this site grades evidence and picks sources, see the immune function research guide and the site’s safety and interactions guide.
Frequently Asked Questions
Can mushrooms support a cold or the flu?
No. Some human trials found that beta-glucan supplements were linked to fewer or shorter cold symptoms in certain groups, but no research shows that mushrooms support or prevent respiratory infections.
Can Cordyceps replace my COPD inhaler or medication?
No. Clinical research on Cordyceps and COPD has studied it as an add-on to standard treatment, not as a replacement. Any change to a COPD treatment plan should be made through the clinician managing the condition.
Are mushroom supplements safe for everyone?
Not necessarily. People with mushroom or mold allergies, autoimmune conditions, bleeding disorders, or those on blood thinners or immune-suppressing medication should talk with a healthcare provider before use, since these groups were often excluded from or underrepresented in the studies described above.
Where can I check if a mushroom supplement interacts with my medication?
A pharmacist or prescribing clinician is the most reliable resource, since they can review your full medication list. This site’s safety and interactions guide also covers known interaction concerns by species.
Educational Disclaimer
This article is for general education only and is not medical advice. It does not diagnose any condition, recommend any treatment, or establish that any mushroom product is safe or effective for a specific person. Always talk with a qualified healthcare provider before starting, stopping, or changing any medication or supplement, especially if you have a lung condition, a chronic illness, or take prescription drugs. If you are experiencing a medical emergency, call your local emergency number right away.