Coriolus Versicolor (Turkey Tail) – The Facts

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Coriolus versicolor (also known under the names Trametes versicolor, Yun Zhi, Kawaratake and Turkey Tail) is probably the most intensively researched medicinal mushroom in the world, due to its outstanding properties as a biological response modifier. (BRM : agent capable of stimulating the immune system and as a result of that expressing various therapeutic effects).

After reading the information below, you still want more information? For a dedicated website we can recommend this link.


Even though this colorful mushroom can be found all over the world, until recently its medicinal qualities were only appreciated in South East-Asia, where mushrooms are highly valued and an important part of the traditional medicinal systems. In the old days teas and soup-like decoctions where a common way to use it.

YunZhi (or Yun Zhi, which means ‘cloud mushroom’) was mentioned in the first written text on medicinal herbs, Shennong Ben Cao Jing, (around 200 BC – Han Dynasty). There is also a record in the Compendium of Materia Medica (Ben Cao Gang Mu) by Li ShiZhen (15th century – Ming dynasty): “The black and green Yun Zhi are beneficial to one’s spirit and vital energy and strengthen one’s tendon and bone. If Yun Zhi is taken for a long time, it will make one vigorous and live long“. Teas and decoctions made of the mushrooms fruiting body were used to improve general health and vitality.

trametes versicolor

Coriolus Versicolor in its natural habitat

Around 1965 Coriolus versicolor was discovered by modern science. A popular (but unverifiable) story circulating on the internet goes as follows: a chemical engineer working for the Japanese Kureha Chemical Industry Company Ltd., observed his neighbor attempting to cure himself of gastric cancer after having been rejected for treatment by the hospitals. The man turned towards a traditional medicine, Saru-no-koshikake, which is a tea made from the Coriolus versicolor. He used this for several months and, amazingly enough, he managed to cure himself. The engineer was intrigued and convinced his employer to investigate the mushroom in depth.

The rest is history. Kureha Labs. managed to isolate active compounds from the mycellium (the underground ‘roots’ of the mushroom) and identified the most potent mycelia strain (CM-101). The mycelia contained a very specific type of protein-linked polysaccharide (beta-glucan), which seemed to be responsible for its therapeutic effects. Such a compound is called “proteo-glycan” or “glyco-protein“.


This PSK (PolySaccharide-Kureha) was discovered and isolated for the first time in 1969. The isolation protocol was patented and after several years of research and clinical trials the product was ratified as an official medicine under the brandname Krestin in 1977 by the Japanese Ministry of Health.

Prof Q.Y. Yang

Prof Q.Y. Yang

Five years later the Chinese professor Qing-yao Yang managed to isolate an even more potent variation from a different strain of mycelia; PSP.

PSP (polysaccharopeptide) was ratified as an official medicine by the Chinese Government in 1992/93.

In the rest of the world both Krestin and PSP are not seen as medication, not because they do not work, but, to quote the Spanish Health authorities (1983): ‘due to the lack of a single identifiable active ingredient which could define the “mechanism of action‘. The American FDA shared this opinion a little bit later.

We quote an American oncologist ( Dr. West, M.D.) to illustrate the general knowledge (or lack thereof) about Krestin and related medication:”There may well be a significant literature on Krestin/PSK, but neither of these terms appears in the index of any of the four most complete tomes I have on the subject of oncology and cancer drugs, covering about 8500 pages on the subject in total. These are American books that I’m sure don’t cover every drug used elsewhere, but those terms have never been mentioned in my presence or appeared on any page I’ve had occasion to read in my medical training. While it may be well-known in Asia, it’s not really a topic covered in the US-based literature.

Krestin sachet

Krestin is sold as powder in 1 gram sachets

Around 1987 Krestin ranked as nr. 1 in Japan as the most used anti-cancer medication, taking 25% of the health insurance budget. Countless dietary supplements based on Turkey Tail are for sale all over the world, but most of the time these are no more than simple hot water extracts of the fruiting body (limited therapeutic effect) or dried and powdered Coriolus fruiting bodies or mycelium biomass (mostly indigestible, so limited effect).

Of course the sellers in general will refer to all the scientific research and ‘contains PSK/PSP!’ can be read on more supplement labels than is justified.

According to an expert in the field of medicinal mushrooms, John Seleen, even PSK is no longer what it is supposed to be:

“[…] Even the pharmaceutical company making “PSK” is running a scam.  If you read the manufacturing patent, the basis for getting the patent is that their extraction process can get more PSK out of the raw material than a straight forward hot water extract.  However, in the patent they clearly state that hot water extraction alone does produce PSK.


However, Kureha does not even use the patented process to make their product for the Japanese market.  They grow mycelium in liquid and use that as the raw material to extract from.  They grow it in large stainless steel bio-reactors.  However, you do not need to save money on the mycelium, it is the cheapest part of the entire process.  You sterilize broth in the bio-reactor (grain and water), introduce a live culture, and 48 hours later you have metric tons of mycelium. It is almost free.  To use their [patented] process, of increasing alkalinity which then forces you to salt it out would be hundreds if not thousands of times more expensive that just making a straight hot water extract (dehydrated) at 42% – 46% polysaccharide. 

That is the potency of PSK sold in Japan, so obviously they are not using the patented process if the patented process doubles and triples recovery of actives.  In fact 10% of the PSK sold on the Japanese market is made in China and [has been] extracted from mushroom fruit bodies.

“PSK” has been part of various scams since its inception.


PSP and PSK have each been extracted from specific strains of the Coriolus mycelia (Cov-1® and CM-101, respectively), and each needs a specific extraction protocol to get the results (as described  in the patents). Below is a table outlining the main differences between PSP and PSK.

Comparison of some characteristics of PSP and PSK

Items compared Similarities Dissimilarities
Fungi Coriolus versicolor (Fr.) Quel (Yun Zhi) mycellium PSP: Cov-1 strain
: CM-101 strain
Drug produced PSP: capsules @ 350 mg
: powder in sachet @ 1 gram
Powder color brown PSP: yellow-brown
PSK: dark brown
Raw materials deep-layer cultivated mycelia (2N)
Fermentation technology with glucose as the main carbon source (25oC) PSP: nitrogenous source: soya bean cake powder, fermentation takes 64 hours

PSK: nitrogenous source: peptone and yeast cake, fermentation takes 10 days

Extract and isolate obtained by immersion in hot water PSP: isolate by alcoholic precipitation

PSK: isolate by salting out with (NH4)2SO4

Medicinal ingredients protein bound polysaccharide; average molecular wt. 1 x 105Dathe polysaccharide is formed from many monosaccharides containing
alpha-1,4 and beta-1,3 glucoside linkage. Peptide mainly consists of aspartic and glutamic acids.
PSP: polysaccharides contain arabinose and rhamnose, but no fucose

PSK: polysaccharides do not contain arabinose and rhamnose, but contain fucose

Pharmacological function inhibits the synthesis of nucleic acid of Ehrlich ascitic cells, and inhibit the accretion of cancer cells of Sarcoma-180, P388 leukocytes, etc. PSP: inhibiting rate on P388 is 90-96% (1mg/kg)

PSK: inhibiting rate on P388 is 61-90% (1mg/kg)

recover the delayed supersensitive reaction inhibited by chemo-therapeutic drugs such as cyclophosphamide and raise the lowered no. of white blood cells. Inhibiting rate, Sarcoma-180 (in Kunming mice)

PSP: 43%;

PSK: 28%.

obviously raise the activity of NK cells and macrophages, raise the contents of immunoglobulin, complement C3,antibody HC50 and IL-2 and promote the increase of T-lymphocytes PSP can increase the alpha and gamma interferons produced by white blood cells 2 to 4 times
Toxic test LD50>20g/kg; Ames test and the tests of abnormal chromosomes,nucleotide, reproduction, and abnormality are all negative. Used 50 times the clinical dosage with monkeys, consecutively for 6 months, caused no toxic reaction. PSP can produce the toxic reaction by making the aggregation of the chromosomes of the lung cancer cells, but there is no direct toxic function on the cancer cells of normal mice.
Clinical effect lessens the toxic and side effects of chemo- and radiotherapy, increases the immune function, promotes the curative effect,and increases the quality of life and the survival rate PSP can not only increase appetite during treatment, but also relieves pain.


Effect of PSP

COV-1 Mycelia

COV-1 Mycelia

PSP is usually administered orally, it works as well as intravenously but requires a lower purity, thus making it more affordable. Many patients have taken PSP consecutively for a decade or more and no adverse effect or contraindication has ever been found.

The effects in the body, when described in brief, are as follows. As said, PSP works on the immune system, so most (but not all) of its workings are indirect. It increases the number of white blood cells when this is too low, it will stimulate the creation and the activity of macrophages, T-cells (including T-helper cells, cytotoxic T-cells and lymphocytes) and NK (natural killer)-cells, all of which are part of the body’s defense system against pathogens. It has both direct and indirect anti-inflammatory, anti-viral and detoxing properties and supports the liver function (our body’s chemical processing plant).

The human immune system is a very complex and still not fully understood structure, essential for our survival. (See this link for an easy-to-understand introduction – opens in a new window).

A major problem with pharmaceutical medication is its level of toxicity – quite a few pharmaceuticals are apart from their desired therapeutic action also causing direct or indirect damage to the immune system and/or the liver or kidneys, which can create a negative chain of events, in particular in the elderly or sick. (It is obvious that heavy medication like chemo cocktails etc. are the worst – they can cause over time the same conditions they are supposed to fight, like metastasis).

It is known that in general after 35 the human immune system starts to get sloppy and after 50 it starts declining. Many old-age related diseases are a direct or indirect result of a flawed immune function. Add this to the pharmaceutical assaults we already mentioned and the general stress of life itself, and it is obvious that some support is needed if we want to maintain the same level of health we were used to when young.

Clinical trials with PSP

Often, when confronted with research related to medicinal mushroom products Western health practioners will say “Very nice!! So it’s good for mice! But what about clinical tests? Where are the clinical trials to prove all this?” They do have a point, of course. But clinical trials are increasingly difficult to realize due to the time and costs and restrictions involved. In fact, the only ones who can afford to finance these tests nowadays are the pharmaceutical industries. And they are not really interested in all-natural medication. They can’t make money on it, because it’s not patentable. They make more money selling chemo-cocktails than they would when selling people a preventive medicine like an immune supporter.

However, both PSP and PSK have been the subject of an array of clinical tests, all performed during the 70’s, 80’s and 90’s. A very complete overview can be found here (pdf-file : page 9 – 19).

Summary of a clinical trial with PSP (1991-1997, Shanghai)

In Phase 1 the toxidity was examined. Twenty-one people, consisting of 16 healthy volunteers and 5 post-operative breast cancer patients (but without recurrence or metastases) were involved. They were given large doses of PSP. No significant toxic side effects or adverse reactions related to PSP intake were found. Four people mentioned light diarrea.

Positive effects of taking PSP were also noted. Eleven people (52.8%) developed an increase of appetite, which was most noticeable in the group taking six grams of PSP/day. Based on the results of this study, PSP was considered safe to use clinically and a Phase 2 clinical trial was undertaken with cancer patients.

In Phase 2 the safety and efficacy of PSP while using it to support chemo- and radiation therapy was investigated. It was a double blind study. 485 cancer patients were involved, with either stomach, lung or esophagic cancer.

All patients received two courses of chemotherapy or radiation depending on the type of cancer. Each course lasted approximately one month. Patients in the treatment group (who did not know they were given PSP) received three 0.340 gram capsules of PSP three times a day. Patients in the open group (both patients and doctors knew they were given PSP) also received the same PSP dosing schedule as patients in the treatment group. The control group got a placebo.

An important finding was the effectiveness of PSP in improving the immunological profiles of the patients. The rate of increase in activity of natural killer cells (NK) in the treatment (63.97%) and open groups (68.93%) was significantly higher than the control group (4.11%). Overall, the Phase 2 clinical trial showed that PSP is safe and can help lessen the side effects that chemotherapy and radiation produces. It also improved or maintained the immunological profiles of all stomach, esophagus and lung cancer patients.

In Phase 3 650 patients with either stomach, lung or esophageal cancer were involved. The Phase 3 trial showed similar results as the Phase 2 trial. The overall response rate for the treatment group (87.5%) was significantly higher than the control group (41.9%). This result suggests PSP helps cancer patients to maintain their quality of life and level of functioning after chemotherapy and radiation by decreasing cancer treatment-related symptoms such as fatigue, loss of appetite, nausea and vomiting and pain in patients.

The full report can be downloaded here.

Currently in the US and Europe some small trials organized by the American Cancer Institute (involving breast cancer patients) are in progress. Check these links (phase 1) and (phase 4) to verify.

A 2012 research report was testing the effects of a PSP extract on dogs with hemangiosarcoma , with very positive results. For more details, see here (opens in new window).

Summarizing, we can state that PSP is an excellent health supporter because it helps to balance the foundation of our health itself: our immune function.

It will be most benificial for those under stress, under treatment (i.p. cancer treatment) and the elderly, whose immune system is declining. Obviously, those with immune-related diseases will also benefit from PSP.


Oriveda PSP-50 was prepared in China using the original patented methods. Its properties are the properties of the original ratified PSP medicine, with the only real difference being a higher level of actives, the result of 21st century pharmaceutical techniques.

In contrast with the Asian products ORIVeDA specifies the level of polypeptides plus the percentage of polysaccharides and the exact percentage of (1>3)(1>6)Beta-D-glucans: in our latest batch over 23% of the polysaccharides were Beta-D-glucans (with 100% bio-availability).

The (1>4)(1>6)Beta-D-glucans (unique for Coriolus versicolor) cannot be listed because no standardized analytical procedure exists currently.

Non-extracted mushroom products are mostly indigestible by humans, since mushrooms are made of chitin, not cellulose, like plants. Heat is needed to break the chitin cell walls and to release the bioactives. Most of the time hot water is used to start the extraction process.

Full information about extraction and why it is absolutely necessary with mushroom products can be found here.  A great and objective, easy-to-follow guideline on how to separate the bad from the reliable mushroom supplements can be found here (also reveals why it’s best not to spend your money on tinctures..).

This monograph is mainly based on the following literature:
-PSP in clinical cancer therapy – A brief overview of Phase I, II and III trialsProf. Qing-yao Yang – Shanghai Teachers Academy, 2000

-Polysaccharopeptides of Coriolus versicolor: physiological activity, uses, and production – Jian Cui, Yusuf Chisti – Biotechnology Advances 21 (2003) 109–122

-PSP and PSK – Shanghai Teachers University

These publications and many others can be found, free for download, here.

4 thoughts on “Coriolus Versicolor (Turkey Tail) – The Facts

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