Coriolus versicolor goes by a number of botanical names, including Trametes versicolor, Boletus versicolor, Polyporus versicolor, Polystictus versicolor, and the common idiomatic attribution of “turkey tail.” The fruiting bodies do resemble a turkey tail in full plumage and the versicolor name comes from this mushroom being variously colored. In Japan it’s called “kawaratake,” which means mushroom by the river bank. Among the common people in China, the fungus is referred to as “yun-zhi,” indicating that it’s a cloud fungus and grows best in the rain.

As an often seen denizen of the woods populating the temperate zones of North America, Asia, and Europe, Coriolus versicolor possesses fan-shaped fruiting bodies which grow in overlapping clusters on dead trees. The mushroom’s top portion is zoned, usually in shades of brown, white, grey, or blue, and it sports hairy bands. The underside of its cap is white and shows minute pores which do not discolor after scratching.

The Active Medicinal Components

The mushroom’s active medicinal components-biological response modifiers which are protein-bound polysaccharides can be found in both the fungus’ fruiting body and its mycelium (the vegetative stage). Although these concentrated polysaccharide extracts are sold under a variety of trade names in North America and Asia, they are most commonly referred to by the Japanese language designated, water-soluble “Polysaccharide Kureha” or Polysaccharide K (commonly referred to as PSK by those informed patients using Coriolus versicolor). PSK contains the main components of -1,4- and -1,6- glucans with -1,3- and 1,6- linkages. Also the mushroom contains other medicinal components of secondary importance.

All of these potent but safely used medicinal components are reported as effective against stomach (gastric) cancer, uterine cancer, colon cancer, and lung cancer.

As clinically and anecdotally reported below, the mushroom extract additionally works well against colorectal cancer, prostate cancer, breast cancer, and liver cancer.

PSK Acts Alone Against Colorectal Cancer

Publishing in Cancer Immunology and Immunotherapy, no less than 11 oncological researchers representing six prestigious medical schools in Japan conducted a randomized double-blind trial on 111 patients who had colorectal cancer. After they had undergone surgical operations for their cancers, 56 patients were given PSK alone as an active treatment substance, and 55 other post surgical patients merely received a placebo.

Comparing the two groups, these eleven medical researchers advised, “There is significant prolongation of disease-free periods for patients with colorectal cancer who took PSK. Additionally. polymorphonuclear leukocytes from patients treated with Coriolus versicolor showed remarkable enhancement in their activities, such as random and/or chemotactic locomotion, and phagocytosis.

In conclusion, PSK was useful as a maintenance therapy for patients after their curative surgical operations for colorectal cancer. The beneficial effects were probably due to the activation of leukocyte functions as one of the many biological-response-modifying activities induced by PSK.

Kenneth Bock, MD Observes PSK Boosts NK Cells

“Because it increases natural killer [NK] cell activity, I think of using Coriolus versicolor mainly when I’m confronted with a patient suffering from cancer or a viral infection,” says Kenneth A. Bock, MD, medical director of two wholistic medical clinics, one located in Rhinebeck, New York and the other in Albany, New York. “This mushroom is one of the main medicinal compounds I use to boost a diminished blood reading which records NK activity. PSK does produce a marked improvement in NK cell function and number, something I monitor by testing. If the blood reading is low, my patient takes greater amounts of PSK capsules. And, although it’s an expensive and sophisticated assay, I repeat my NK cell testing inside of a month or two. In a number of patients, I’ve seen some nice blood test improvements.

“Before consulting me, a few patients with advanced metastatic cancer show NK cell activities of only 2 or 3 minute units (m/u). Normal measurements for the laboratory I employ is between 20 and 50 m/u. By using PSK for most of these patients, I have observed their NK cells increasing into the normal range. They then experience an improved prognosis,” says Dr. Bock. “I can illustrate what I’m saying by providing a before-and-after patient case history plus the literature that backs my claim.

“Here is a white, married male with the initials M.E., 60 years old, working as a computer consultant, who originally had been followed medically for hypertension, hyperlipidemia, and arteriosclerosis, during 1995. He also exhibited laryngeal polyps which were cancerous. M.E. received radiation therapy as a followup to the surgery performed to remove these polyps,” points out Dr. Bock. “At the time of surgery, a CT scan to his pelvis was negative for cancer metastasis to the prostate. But later, in April 1997, M.E. did show an elevated PSA [prostate-specific antigen] and underwent an additional medical workup, including biopsy. Workup results indicated his true diagnosis, which was prostate cancer. His blood test showed diminished natural killer cell activity at the level of 6 m/u. Still, M.E. wanted no conventional therapy for the prostate cancer,” Dr. Bock tells me. “So I started him on alternative medical therapies for prostate cancer and to improve his deficient NK cell activity. Coriolus versicolor was a definite part of M.E.’s treatment regimen. “Within two months, the patient’s NK cell activity elevated to 18 m/u. And two months after that his NK cell activity increased to a normal 31 m/u. Now M.E. is doing well physically, and he tells me he feels great! I would say that this type of response to PSK therapy is usual; the patient’s quality of life does improve dramatically and he or she feels a sense of wellbeing,” Dr. Bock states.

Kenneth A. Bock, MD, lectures extensively to health professionals and consumer groups on wholistic medicine. Engaged in family practice, Dr. Bock specializes in treating patients for allergies; plus, he treats heart and blood vessel diseases for which he employs chelation therapy, nutritional therapies, and preventive medicine.

Animal Studies of Coriolus versicolor

Animal studies investigating the efficacy of Coriolus versicolor indicate it has marked immune system-enhancing activity and a broad antineoplastic scope. It prolongs the survival time of irradiated (cancer-induced) mice by stimulating phagocytic activity of macrophages and improving the functions of the reticuloendothelial system. For another rodent-type of disease, cyclophosphamide-induced granulocytopenia in mice, PSK caused a significant increase in granulocyte production. Also it restored antibody (IgG) production in mice bearing sarcoma 180, but not in normal mice.

PSK acts directly against tumor cells as well as indirectly in the host to boost cellular immunity. The following is a listing of cancers for which it is known to be efficacious in animals: adenosarcoma, fibrosarcoma, mastocytoma, plasmacytoma, melanoma, sarcoma, carcinoma, mammary cancer, colon cancer, and lung cancer. Indeed, injection of the PSK compound at one tumor site shows tumor growth inhibition at other sites, thus helping to prevent metastasis. Moreover, its antitumor activity increases when PSK is administered in combination with radiation, chemotherapy, or immunotherapy. Giving the polysaccharide substance in 10% or less of rat feeds does suppress carcinogen-induced rodent cancers of the colon, esophagus, breast, and lung.

PSK demonstrates antiviral activity and may be effective against the human immunodeficiency virus (HIV) infection by modifying the viral receptor or by stopping it from binding with lymphocytes. Another mechanism through which PSK shows general antiviral activity is through the stimulation of interferon production.

Whole Coriolus versicolor lowers serum cholesterol in animals. In combination with the herb Astragalus membranaceus Bunge, it enhances neutrophil function and speeds recovery in rabbits suffering from burns. A powdered extract of PSK from the 70% ethanol tincture of this species tested in rats by injection in a Hippocratic screening of higher fungi did demonstrate mild tranquilizing and diuretic effects.

PSK is Supportive of Chemotherapy/Radiotherapy

Providing strong benefits for the immune system when given alone, Coriolus versicolor works even more supportively against cancer after it's applied with chemotherapy and/or radiotherapy. In fact, out of 200 adjunctive phytochemicals screened for antitumor activity by Japanese researchers in 1971, PSK was selected as the best adjunctive treatment.

The researchers suggested that this medicinal mushroom seemed to protect the immune system’s activity from being suppressed by the chemotherapy drugs and by the toxic processes of the cancer itself. Added to that finding, a ten year study of 185 patients with lung cancer showed that combining PSK with radiation therapy produced “satisfactory” tumor shrinkage and better survival rates for patients with stage I cancer (39%) and stage II cancer (22%) compared against those patients with stage I cancer (16%) and stage II cancer (5%) who did not receive this combination of therapies.

Reporting the above study in another more exacting way: From 1976 to 1985, 185 patients with non-small cell lung cancer at stages I, II, and III were treated with definitive radiotherapy in Gunma University Hospital at the Gunma University School of Medicine in Maebashi, Japan. The long term survivors were analyzed carefully. Those who had received Coriolus versicolor as adjunctive treatment showed more satisfactory tumor shrinkage and their five year survival rate was better than those patients not receiving PSK. That is, PSK patients with stages I or II disease showed up with 39% survival; PSK patients with stage III cancer had 22% survival. Comparing these survivors with the stage I and stage II non-PSK group, we see that these non-PSK patients had only 16% and 5% survival, respectively. The non-PSK stage III patients had no survivors.

In Japan, the standard adjunctive treatment after resection of gastric cancer is a combination of two cytotoxic drugs, intravenous mitomycin plus oral fluorouracil. As a clinical test, the protein-bound polysaccharide PSK was added to this standard chemotherapy for 262 randomly assigned patients. Half received Coriolus versicolor and half took the usual chemotherapy alone after all of them had undergone what the Japanese label as “curative” gastrectomy. During a minimum followup of five years (ranging from five to seven years), the clinical testing took place at 46 institutions in central Japan.

PSK improved the cancer patients’ five-year, disease-free rate at 70.7% versus 59.4% in a standard treatment group (p=0.047). And it improved their five-year survival rate at 73.0% versus 60.0%, (p=0.044) as well. The two regimens had only slight toxic effects, consisting of nausea, leucopenia, and liver function impairment. There were no significant differences between the groups. The treatments were clinically well tolerated and compliance of patients was good. In their paper published in Lancet, the researchers concluded, “Addition of PSK to adjunctive chemotherapy with mitomycin and fluorouracil is beneficial as treatment after curative gastrectomy.”

Between January 1980 and December 1990, 227 operable breast cancer patients with vascular invasion in their tumors and/or in their metastatic lymph nodes were randomized into three treatment groups. Group one received a combination of toxic therapies, what the researchers labeled as “FEMP” (5-fluorouracil, cyclophosphamid, mitomycin C, and predonisone). Group two received FEMP plus LMS (levamisole). Group three received FEMP plus PSK.

The seven Japanese researchers concluded: “Immunochemotherapy using PSK improved the prognosis of patients having operable breast cancer with vascular invasion..The prognosis of the FEMP + PSK group tended to be better than that of the FEMP group. FEMP + PSK is better because of its usefulness including good compliance.

Twenty-eight patients suffering from acute leukemia who had achieved complete remission participated in a clinical trial. Starting in September 1976, half of these patients entering the chemo-PSK immunotherapy group received the medicinal mushroom, Coriolus versicolor, and half entering the strictly chemotherapy group did not. To retain the patients’ remission, all of them received three courses of the chemotherapy combination of cytoxics consisting of 40 units/kg/day of neocarzinostatin; 0.8 -1.6 mg/kg/day of cytosine arabinoside; 0.6 - 0.8 mg/ kg/day of daunorubicin; and 0.8 -1.6 mg/kg/day of prednisolone on days one to four for acute non-lymphocytic leukemia, and 0.04 mg/kg/day of vincristine on day one: 0.6 - 0.8 mg/kg/day of daunorubicin; and 0.8 - 1.6 mg/kg/day of prednisolone on days one to four for acute Lymphocytic leukemia.

The durations of complete remission and survival in the chemo-PSK immunotherapy group (receiving PSK) showed significant prolongation compared to that of the Strictly chemotherapy group (not receiving PSK). The median duration of complete remission for this PSK group was thirty-six weeks and that for the non-PSK group was twenty-five weeks. The average survival time from diagnosis of the PSK group was twenty-one months and that of the non-PSK group was twelve months.

Tori Hudson, ND, Uses Coriolus versicolor

“The only condition I’ve been using Coriolus versicolor for is breast cancer, stage II and above, in which the patients have been actively receiving chemotherapy. If they are just starting their chemotherapy, I’ve added PSK. When the patients are finished with their chemotherapy I’ve continued the PSK. This procedure is followed in accordance with my understanding of the few research articles I’ve read relative to breast cancer patients and PSK. My intention is to keep the breast cancer patient taking Coriolus versicolor for a total of five years. But I’ve been using the mushroom for only a year now,” says naturopathic physician Tori Hudson, ND.

Dr. Tori Hudson, whom all of us recognize as a columnist for the Townsend Letter for Doctors & Patients, is a professor teaching at the National College of Naturopathic Medicine in Portland. She is health care director at her Portland, Oregon clinic which operates under the name: “A Woman’s Time.” “I have just begun using PSK for a man who is facing the recurrence of gastric cancer. He’s had a full gamut of therapies and still shows elevated cancer markers which his oncologist finds untreatable. The patient was referred to me for some alternative cancer therapy because conventional oncology has nothing more to use on him,” says Dr. Hudson. “My impression is that patients taking Coriolus versicolor are experiencing less side effects from chemotherapy such as diminished fatigue, less nausea, (but not less hair loss), and more stable white blood cell counts. I have not measured the natural killer cell counts.”

A Patient’s Experience with Liver Cancer Reduction

A 64 year-old electrical engineer in Tyler, Texas. Allen Greenstaff had been doctoring with liver cancer for six years. In the beginning stages of his malignancy, he took chemotherapy which eventually proved to do no good. And the oncologist offered him absolutely nothing more as treatment, not even personal care to accomplish a better quality of life for himself - no improved diet, nutrients, exercise, meditation - just nothing at all.

“That doctor was the most negative man I ever met,” said Mr. Greenstaff. “After the chemo failed, he threw up his hands, shrugged his shoulders, wished me good luck, and said there was nothing else he could do. And surgery couldn’t be performed either, because the consulting surgeon saw that the tumor was wrapped around my vena cava blood vessel.”

The patient replied to his oncologist, “I totally reject what you are telling me. I do not accept that nothing can be done to affect the outcome of this disease.” When the doctor said, “Well, I know what I’m talking about when it comes to cancer. I’m a scientist,” Allen Greenstaff shot back, “Yes, but you’re not God!”

Even with being abandoned by his oncologist, today the patient is healthy once again after utilizing alternative methods of healing, most especially by his self-administration of oral Coriolus versicolor. Mr. Greenstaff’s tumor, which had been situated on the left lobe of the liver, was sized at 10 cm by 7 cm and by the longitudinal measurement of 9 cm. Now, after he has been taking capsules of PSK, the tumor has shrunk to 6 cm by 4 cm by 3 cm (longitudinally). The patient had learned about Coriolus versicolor from his contacting Medline on the internet. By digging into the world wide web, he has saved himself. Remarkably, the volume of Mr. Greenstaff’s liver cancer has reduced to less than 10% of its original size, from 630 cm down to 60 cm. And his carcinoembryonic antigen (CEA) cancer marker has improved dramatically as well, dropping from 296 to 97.9.

Today, after two years, Mr. Greenstaff still swallows those usual, brownish colored mushroom capsules, which he intends to take the rest of his life. He is well-versed in the efficacy of Coriolus versicolor, since the man has read nearly 400 studies about PSK that he printed out from the internet.

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IMPORTANT NOTICE: The information provided above has not been evaluated by the FDA, is for educational purposes only and is not intended to replace proper medical care, diagnose or prescribe. The use of Coriolus versicolor extract is meant to be used as nutritional support, not for the treatment of any disease. Your medical condition should be discussed with your physician before using this product.