"Mushrooms as medicine" means very different things in different countries. In Japan and China, doctors prescribe certain mushroom-derived drugs (like PSK and lentinan) as adjuncts in specific hospital settings. But such claims are not allowed in the U.S., where mushrooms are foods and dietary supplements, only. Below we explain both worlds and delve into how doctors in Asia use some mushrooms as medicine to enhance patient outcomes. Let's get to it!
Key Takeaways
- “Medicine” is a legal term in the U.S. Only FDA-approved pharmaceuticals are “medicines.” Mushroom products sold here are foods or dietary supplements and cannot claim to diagnose, treat, cure, or prevent disease. Supplements are not medicine.
- Asia uses some mushrooms as doctor-prescribed medicines. In Japan, China, and parts of Korea, purified mushroom compounds are locally approved and used in hospitals -- often as adjuncts to standard care.
- Mushrooms used as medicine are not the same as supplements. Doctor-prescribed mushrooms are precise, with defined molecular specifications; supplements may vary widely by species ID, extraction, and active compound content.
- Two worlds, two rulebooks. Doctor-used products overseas are standardized, prescription-only medicines with defined dosing and oversight. U.S./EU retail mushroom products are supplements intended to support normal biological functions.
- Adjuncts and adjuvants. These terms refer to how mushrooms are used as doctor-prescribed treatments that are not primary first-line treatments, but are rather used as a secondary treatment or for overall support of the main treatment.
- Evidence is promising. Human studies show small-to-moderate effects that depend on species, extract, dose, and duration. Late-phase trials (for some indications) are ongoing.
- Safety is generally good, with caveats. Most people tolerate standardized extracts; possible GI upset, rare allergies, and potential interactions (e.g., with anticoagulants, immunosuppressants, hypoglycemics).
Disclaimer
This article is for general information and education. It is not medical advice and is not a substitute for diagnosis, treatment, or personalized recommendations from a qualified healthcare professional. “Medicine” is a legal term. In the United States, only FDA-approved pharmaceutical products are recognized as medicines for the diagnosis, treatment, cure, or prevention of disease. Mushroom products offered for sale here are foods or dietary supplements and are not medicines. References to doctor-prescribed mushroom products used in Asia (e.g., Japan/China/Korea) describe locally approved medicines or physician-prescribed traditional formulas within those healthcare systems. Such products are not approved as drugs in the U.S. and may not be available outside their jurisdictions. Any benefits discussed for U.S./EU consumer products are limited to structure/function support (e.g., “supports healthy immune function”) and do not imply treatment or prevention of any disease. Speak with your physician before using any mushroom supplement, especially if you are pregnant or nursing, preparing for surgery, have a medical condition, or take medications (e.g., anticoagulants, immunosuppressants, hypoglycemics).
Mushrooms as Medicine: What the Phrase Really Means
Let’s address the elephant in the room: in the United States, “medicine” is a legal term reserved for pharmaceutical drugs approved by the FDA to diagnose, treat, cure, or prevent disease.
By law, functional mushroom products sold in the US as foods or dietary supplements are not medicines -- and we can’t (and won’t!) claim they treat any disease.
What we can say -- accurately and responsibly -- is that mushroom foods and extracts can support aspects of health (for example, immune function, stress resilience, cognitive performance, and skin hydration) when used as part of a healthy lifestyle.
Why the wording matters (semantics and compliance)
“Mushrooms as medicine” and "medicinal mushrooms" are powerful phrases for search and everyday speech, but in U.S. regulatory language they are not really accurate.
Under DSHEA (the Dietary Supplement Health and Education Act), companies may make structure/function statements about mushrooms, such as “supports healthy immune function” -- but must avoid disease claims like “treats infections” or “prevents cancer.” Technically under DSHEA, mushrooms cannot be "medicine" because only pharmaceutical drugs may be classified as such.
That’s why you’ll see careful phrasing throughout this article -- even when we discuss impressive research -- so readers get clarity without crossing legal lines.
In Asia, mushrooms are both traditional herbs and modern medicines.
Across East Asia, mushrooms hold a dual identity:
- Traditional herbal tonics: Reishi (Lingzhi), Shiitake, Turkey Tail, Lion's Mane Mushroom, maitake mushrooms, oyster mushroom and others have been consumed for centuries as food-tonics to nourish vitality, “balance” the body, and support seasonal resilience.
- Physician-prescribed drugs: In countries like Japan and China, certain purified mushroom compounds are approved as hospital-use medicines (often as adjuncts to standard care).
Some examples of mushroom compounds that are used as medicine in Asia include:
- Lentinan (from Shiitake): Made from shiitake mushroom extracts; an injectable beta-glucan-based adjuvant used in oncology settings (Japan).
- PSK (Krestin) and PSP (from Turkey Tail): Orally administered polysaccharide complexes used as physician-directed adjuncts (Japan/China).
- Schizophyllan/Sizofiran (from Schizophyllum commune): a beta-glucan-class injectable used for specific indications (Japan).
These products are not culinary mushrooms or over-the-counter supplements; they are regulated medicines with precise compositions, dosing, and clinical protocols, prescribed and monitored by physicians within those healthcare systems. We'll detail these and other mushroom compounds below.
Medicine vs. Supplement: Why the difference in how mushrooms are framed?
The difference comes down to regulatory pathways and medical tradition:
- Regulatory pathways: Japan’s and China’s systems recognize certain purified natural products as drugs after local clinical evaluation, even when those ingredients originate in common foods or herbs. The U.S., by contrast, separates drugs (requiring FDA approval for disease claims) from dietary supplements (like multivitamins) which cannot claim to treat disease.
- Integration with traditional medicine: East Asian healthcare has longstanding integration between biomedicine and traditional pharmacopeias. That history of integrative medicine helped pave a clinical route for mushroom-derived compounds to become doctor-used medicines in hospitals.
- Standardization and delivery: The Asian “mushroom medicines” are manufactured to drug standards, while Western supplements vary in species, extraction methods, and standardization (for example, a precise percentage of beta-glucans or triterpenes), and are positioned for health support rather than disease treatment.
How this article uses “Mushrooms as Medicine”
We’ll use the phrase "mushrooms as medicine" because many readers search for it -- but we’ll take care to remain clear that dietary supplements are not a substitute for pharmaceutical drug medicine and medical professional care.
First, we’ll describe the physician-prescribed mushroom medicines used in parts of Asia. Then we’ll explore the mushroom foods and supplements available in the U.S. and EU -- what research suggests they can support, how to evaluate quality, and how to use them responsibly as part of a broader wellness plan.
Discover today's top mushrooms for health
Key Takeaway
In the U.S., mushrooms are not “medicine” in the legal sense -- yet they remain valuable as nutrient-dense foods and standardized supplements that can support health. In parts of Asia, certain purified mushroom compounds are legally recognized as medicines and used by doctors under defined indications. Understanding this difference lets us appreciate the science while staying accurate and respectful to compliance guidelines.
Turkey Tail (Trametes versicolor)
A common fungus on hardwood logs, Turkey Tail fans out in colorful, banded semicircles that resemble a turkey's tailfeathers -- hence the name. It's not a culinary star (it has a tough texture), but is traditionally made into a tea in China/Japan for respiratory, digestive and general immune support.
Modern science has discovered that Turkey Tail is rich in polysaccharopeptides, notably PSK and PSP, which have a long history of use in East Asia for immune system support.
In Asia, PSK/PSP are studied and used as adjuvants -- with outcomes often focusing on quality-of-life measures, immune function parameters, and treatment tolerance within a doctor's overall plan.
Contemporary research highlights Turkey Tail's immune modulation effects, activation of frontline immune cells, antioxidant activity and prebiotic effects that can improve gut microbial diversity. A diverse microbiome is important because it correlates with robust immune function and healthy metabolic markers.
Discover today's top prebiotic supplement for nourishing the microbiome
What Doctors Use
Japan: PSK (Krestin). A purified protein-bound polysaccharide manufactured to drug standards. Prescribed by physicians as an adjuvant in specific oncology settings (per Japanese protocols). Dispensed under medical supervision with defined product specifications and quality controls.
China: PSP. A closely related polysaccharide–peptide complex developed and used within China’s state-regulated system. Employed as a hospital-use adjunct to treatments related to oncology, liver problems and respiratory conditions under physician oversight.
In Japan and China, physician-used turkey tail derivatives -- PSK (Krestin, Japan) and PSP (China) -- are regulated medicines given in addition to standard care. They are mostly used as adjuvant to immunochemotherapy after surgery for gastric and colorectal cancers, with use also reported around esophageal and lung cancers. In China, PSP has also been used clinically for liver problems, chronic bronchitis, and related indications under physician oversight.
An interesting fact: Japan’s PSK has been incorporated into national oncology practice for decades and is still studied/used as an adjuvant for cancer patients receiving chemotherapy to support survival outcomes.
Research: A landmark meta-analysis pooling randomized trials in resected gastric cancer found that adding PSK to adjuvant chemotherapy produced a significant survival benefit versus chemotherapy alone with no significant heterogeneity -- supporting PSK as an effective adjuvant in this setting. Subsequent analyses and cohort work from Japan have echoed improved overall survival when PSK is combined with standard regimens.(1)
Key Takeaway: Turkey Tail is a traditional tea in East Asia and a modern source of polysaccharopeptides (PSK/PSP) that support immune function. In Japan and China, drug-standard PSK/PSP are used by doctors as adjuncts to standard care -- especially around gastrointestinal cancers -- while culinary/supplement forms elsewhere are for general wellness support, not disease treatment.
Shiitake
Shiitake is native to East Asia and has been cultivated for centuries -- first documented in Chinese texts and later widely grown in Japan. It is both a culinary staple and a traditional health food. As a traditional herb, shiitake mushroom has long been eaten fresh to support vitality, resilience and respiratory health during cooler months. It has also been used to “fortify the middle” and encourage healthy circulation.
In East Asia -- especially Japan -- compounds derived from shiitake are regulated medicines used by physicians as adjuncts to standard care in specific cases.
What Doctors Use and Why
Lentinan (Japan). A purified, high–molecular-weight beta-glucan produced to drug standards. Typically used as an injectable adjuvant in oncology settings (and sometimes for modest blood lipid support) under physician supervision. Distinct from shiitake supplements, doctor-prescribed lentinan has a specific molecular profile and manufacturing approach.
In the late 20th century, researchers isolated water-soluble beta-glucans from shiitake and introduced lentinan as a standardized pharmaceutical product for physician-directed, hospital use in Japan. It is used an injectable adjuvant (a "boost" to standard treatment regimens).
Lentinan is typically given alongside chemotherapy, most notably for advanced or resected gastric cancer, with use also reported around gastrointestinal and lung cancers under physician protocols. Several Japanese cohorts and reviews note its medicinal properties may help improve survival or quality-of-life measures when added to chemotherapy.
Research: One of the strongest analyses is an individual patient data meta-analysis pooling five randomized trials (n = 650), which found that adding lentinan to chemotherapy prolonged overall survival versus chemotherapy alone. Researchers found that benefits appeared more pronounced in certain subgroups (e.g., node-positive disease), supporting lentinan’s role as a regulated adjuvant in Japan, while underscoring the need for modern clinical trials to further confirm its potential.(2)
Key Takeaway: In Japan, purified shiitake beta-glucan (lentinan) is a doctor-used medicine -- standardized, injectable, and prescribed as an adjunct under clinical protocols. In the U.S. and many other regions, shiitake is available only as a dietary supplement intended to support normal immune function -- not to diagnose, treat, cure, or prevent disease.
Did you know?
Many mushrooms are celebrated as a healthy diet choice. Shiitake is one of the best because they are low in calories and rich in nutrients like B-complex vitamins, copper, and selenium. They are also a notable plant-based source of vitamin D when the mushrooms are exposed to ultraviolet (UV) light, such as from the sun or specialized lamps, offering an accessible way to supplement this essential nutrient.
Schizophyllum commune
Schizophyllum commune -- the “split gill” mushroom -- is a small, fan-shaped wood-decomposer found worldwide on fallen hardwood. Its underside has distinctive gills that split lengthwise as it dries and rehydrates.
In East and Southeast Asian folk cuisine, this mushroom is used as a healthy food, typically simmered in soups and stews for seasonal resilience and overall recovery from health challenges. It’s often paired with warming aromatics like ginger and scallion to support comfortable digestion and nourish overall vitality.
What Doctors Use and Why
Schizophyllan (also known as Sizofiran or SPG): In Japan, purified SPG is used by physicians as an adjuvant alongside standard therapy, most notably in gastric cancer after surgery with chemotherapy, and in cervical cancer with radiotherapy. Clinical studies of SPG report changes in innate/adaptive immune markers and adjunct benefits on patient-reported outcomes when used alongside standard care.
The split-gill mushroom also supplies protein–polysaccharide complexes and fibers that may contribute to its immune-supportive effects, but SPG is the main attraction.
Research: A randomized controlled trial in gastric cancer (Japan; n = 386) compared postoperative chemotherapy with vs. without SPG. While 5-year overall survival didn’t differ across all cancer patients, the curatively resected subgroup (n = 264) had better 5-year survival and lower recurrence when SPG was included; multivariable analysis identified sizofiran administration as an independent predictive factor. Randomized trials reported longer time to recurrence and improved survival in certain settings when SPG was added to conventional treatment.(3)
Key Takeaway: Schizophyllum commune has a unique place in the “mushrooms as medicine” conversation: a traditional food that also yielded schizophyllan, a beta-glucan developed into physician-used drug products in Asia.
We just covered the top three medicinal mushrooms used as medicines in Asia.
Doctor-used mushroom medicines like PSK/PSP (turkey tail), lentinan (shiitake), and schizophyllan (split gill) have their strongest evidence and historical use as adjuvants in gastrointestinal cancers (e.g., gastric/colorectal) and, for schizophyllan, in some gynecologic settings. There are some small or exploratory studies in various tumor types (including breast cancer and prostate cancer), but these have not translated into formal, indication-specific approvals.
Cordyceps (Cordyceps sinensis / militaris)
In the wild, Cordyceps sinensis famously grows from high-altitude caterpillars on the Tibetan Plateau (now rare and protected). Modern supplements responsibly use cultivated strains, especially Cordyceps militaris, which naturally produces cordycepin. In Traditional Chinese Medicine, Cordyceps is a premier Qi tonic -- supporting lungs and kidneys, vitality, and healthy aging.
Cordyceps is often described as a bi-directional immune modulator -- it can help tune both innate (first-line) and adaptive ("learned") responses.
Discover today's top "innate + adaptive" immune supplement
Cordyceps is popular for energy and endurance: research explores support for oxygen utilization, mitochondrial efficiency, and exercise recovery. Additional health benefits discussed include respiratory comfort, libido/vitality, and glucose and lipid balance within a healthy lifestyle.
What Doctors Use and Why
Jinshuibao (CS-4) and Bailing/Corbrin capsules. These are standardized medicines made from cordyceps, manufactured under drug standards and prescribed by doctors. These cordyceps medicines are most commonly administered for chronic kidney disease and respiratory issues such as chronic bronchitis/COPD, with additional use reported in post-infection recovery.
Research: A multicenter, randomized, double-blind, placebo-controlled trial (n=240) tested Bailing capsules for chronic bronchitis across eight Chinese hospitals for 48 weeks; compared with placebo, Bailing significantly reduced acute exacerbation frequency and improved symptom severity (expectoration, wheeze) without increasing adverse events, though breathing test (spirometry) changes were not different. These findings support Bailing as a physician-used adjunct for chronic bronchitis within China’s regulatory framework.(4)
Reishi (Ganoderma lucidum)
The Reishi mushroom (also called Lingzhi or Ling zhi) holds a profound significance in Asian herbal health traditions, especially in Traditional Chinese Medicine (TCM), where it's revered as the "Mushroom of Immortality." With a history spanning over 2,000 years, its rarity in the wild once reserved its use for only royalty and nobility, cementing its symbolic status for longevity, health, and spiritual potency.
TCM practitioners prize Reishi as an adaptogen, a substance believed to help the body resist the damaging effects of stress and restore balance, or Qi (vital energy).
Discover more stress-busting adaptogenic herbs beyond Reishi
Beyond helping to reduce stress, reishi is traditionally used in herbalism to help with a wide range of functions, including optimizing the immune system, calming the mind to ease anxiety and insomnia, and tonifying the heart and liver.
What Doctors Use and Why
Ganoderma sinense polysaccharide (GSP) tablet. Approved in 2010 as an adjunctive therapy for leukopenia and hematopoietic injury during concurrent chemo/radiation.
Ganoderma lucidum polysaccharide (GLPS) injection (“Ji 731”). In large-scale production since the 1980s; used intramuscularly in neurological and supportive-care contexts.
These products are manufactured to drug specifications and prescribed under hospital protocols -- quite distinct from over-the-counter reishi supplements. Doctors in China use regulated “Lingzhi” medicines mostly as adjuncts; GSP tablets during cancer therapy, for example, to protect the body's well-being through chemotherapy and radiation treatment as the patient fights cancer. GLPS injection has also been used in China for neuromuscular conditions under medical supervision.
Research: A focused review in Progress in Molecular Biology and Translational Science summarizes the regulatory approval of GSP tablets in China and compiles evidence that GSP can support white-cell recovery and modulate immune responses when used adjunctively during cancer therapy. The authors also outline beta-glucan-centered mechanisms and safety/tolerability in clinical use. The review frames GSP as a locally approved hospital medicine for managing chemo/radiation-associated hematologic injury, while distinguishing it from non-standardized supplements sold elsewhere.(5)
Key Takeaway: Reishi is a legendary tonic mushroom with a long safety record and promising human research for stress/sleep, fatigue, and immune modulation. Regulated reishi medicines are popularly used in China as medicines and alternative therapies to complement standard treatment protocols for a broad range of health issues.
Poria sclerotium (Wolfiporia cocos; Fu Ling)
Poria is a fungus that grows underground on the roots of pine trees. The hard, dried mass of its mycelium (also called the sclerotium: a dense, coconut-like mass) is used as a tonic in wellness traditions. In East Asian herbalism, Poria (Fu-ling, the sclerotium of Wolfiporia extensa) is used to “drain dampness,” promote urination and stimulate appetite, while strengthening the spleen/digestion and gently calming the spirit. It serves as a neutral, harmonizing base in many classic prescriptions.
What Doctors Use and Why
Choreito. This is an insured Japanese Kampo (traditional Japanese herbal medicine) prescription. Like TCM, Kampo often uses multi-ingredient formulas. Choreito combines Poria sclerotium with Alisma (a water plant rhizome) and other crude drugs, typically standardized and dispensed as extract granules.
In Japan and China, Poria is used as part of a physician-prescribed formula component -- not a standalone drug -- within Kampo/TCM for pattern-guided goals such as acute cystitis in women, urinary tract symptoms, fluid regulation (edema/urinary volume), and digestive comfort. Note, however: the real-world research backing Choreito has investigated Poria as part of a formula with other ingredients, and does not necessarily translate to Poria as a single-herb tonic.
Kampo prescriptions like Choreito are covered by Japan’s national health insurance and routinely written by physicians in both outpatient and inpatient settings.
Modern science has revealed Poria contains polysaccharides (PCP), triterpenoids (e.g., pachymic acid), and sterols. Research suggests immune-modulating activity, microbiome nourishment, mild diuretic effects consistent with traditional use, plus potential benefits for healthy sleep patterns and calm mood via gut–brain pathways.
Research: A nationwide retrospective cohort study assessed women (18-49 years) with first-episode acute cystitis treated with antibiotics with vs. without the Kampo formula Choreito (which contains Poria sclerotium). Among 8,834 eligible patients, adding Choreito was linked to a 5% reduction in total antibiotic prescription days (adjusted beta 0.950; p = 0.038), while clinic visits and prescription counts were unchanged. These results suggest a small but measurable adjunctive benefit in real-world practice.(6)
Key Takeaway: Poria mushroom is included in doctor-prescribed multi-ingredient formulations like Choreito, where its health benefits help to bolster patients' recovery and quality of life.
Summary
“Mushrooms as medicine” means different things depending on where you live. In Japan and China, certain purified compounds from medicinal mushroom varieties -- compounds like PSK, PSP, lentinan, and schizophyllan -- are doctor-prescribed, standardized medicines used as adjuncts within hospital protocols, including some that are used to treat cancer.
In the U.S. and EU, mushrooms you can buy are dietary supplements and traditional foods -- such as lion's mane mushrooms, white button mushrooms, and others. These are useful as complementary and alternative therapies for supporting normal physiological functions, but not approved to diagnose, treat, cure, or prevent disease.
The takeaway is simple: celebrate the science without blurring the lines. When discussing Asian, physician-used products, be clear they are locally approved drugs with defined dosing and oversight; when discussing retail products, use accurate structure/function language and emphasize quality (species ID, extraction method, verified beta-glucans) and safety. If you’re considering adding mushrooms to your routine -- or coordinating them with medical care -- talk with a qualified clinician to ensure they fit your needs, medications, and goals.
Reminder Disclaimer
This article is educational content, not medical advice. “Medicine” is a legal term that, in the United States, applies only to FDA-approved drugs. References to doctor-prescribed mushroom products in Asia describe locally approved medicines or physician-prescribed traditional formulas within those healthcare systems; they are not approved as drugs in the U.S.
Any discussion of mushrooms sold in the U.S./EU pertains to foods or dietary supplements intended for structure/function support (e.g., “supports healthy immune function”) and does not imply diagnosis, treatment, cure, or prevention of disease. Always consult a qualified clinician before starting any mushroom product -- especially if you are pregnant or nursing, preparing for surgery, have a medical condition, or take medications such as anticoagulants, immunosuppressants, or hypoglycemics.
References
- Oba, K. (2007). Efficacy of adjuvant immunochemotherapy with polysaccharide K for patients with curative resections of gastric cancer: A meta-analysis of centrally randomized controlled clinical trials. Cancer Immunology, Immunotherapy, 56(6), 905–911. Link
- Oba, K., Teramukai, S., Kobayashi, M., Matsui, T., Kodera, Y., & Sakamoto, J. (2009). Individual patient-based meta-analysis of lentinan for unresectable/recurrent gastric cancer. Anticancer Research, 29(7), 2739–2745. Link
- Fujimoto, S., Furue, H., Kimura, T., Kondo, T., Orita, K., Taguchi, T., Yoshida, K., & Ogawa, N. (1991). Clinical outcome of postoperative adjuvant immunochemotherapy with sizofiran for patients with resectable gastric cancer: A randomised controlled study. European Journal of Cancer, 27(9), 1114–1118. Link
- Shu, X., Xu, D., Qu, Y., Shang, X., Qiao, K., Feng, C., Cui, H., Zhao, X., Li, Y., Peng, Y., Li, D., & Zhang, H. (2024). Efficacy and safety of Cordyceps sinensis (Hirsutella sinensis, Cs-C-Q80) in chronic bronchitis: A randomized, double-blind, placebo-controlled trial. Frontiers in Pharmacology, 15, 1428216. Link
- Zhang, Y., Jiang, Y., Zhang, M., & Zhang, L. (2019). Ganoderma sinense polysaccharide: An adjunctive drug used for cancer treatment. Progress in Molecular Biology and Translational Science, 163, 165–177. Link
- Sugihara, T., Kamei, J., Yasunaga, H., Sasabuchi, Y., & Fujimura, T. (2022). Prescription of Choreito, a Japanese Kampo medicine, with antimicrobials for treatment of acute cystitis: A retrospective cohort study. Antibiotics, 11(12), 1840. Link
