Essiac Detailed Scientific Review

Overview

Background

In 1922, Rene Caisse, head nurse at a hospital in Ontario, Canada, began providing an herbal tonic to patients with cancer. She said she had learned of this tonic from a woman who had recovered from breast cancer after being given the tonic by an Ojibwa medicine man. The name, “Essiac”, is a registered trademark and is also the Caisse name spelled backwards^1-4. This review will adopt the practice of using “essiac” to include all of the formulas that have developed over time along with specific brand names such as Essiac® or Flor*Essence®.

During the 1920s and 1930s, Caisse treated patients with injectable and oral forms of essiac. One person died following an injection, but it was later determined that he had died from a pulmonary embolism not linked to the injection. Injections were discontinued in the 1950s as ineffective⁵.

Prohibitions were set up by the conventional medical community against the practice of medicine by Caisse, but patients continued to seek her treatment. In 1938, the newly formed Royal Cancer Commission (consisting of six physicians with expertise in cancer) began an investigation by visiting her clinic to interview patients. This was followed by a public hearing attended by 387 patients who hoped to testify for Caisse; however, only 49 were allowed to testify. Arguments ensued as to the correct diagnosis of cases and whether or not essiac could be credited with remission when surgery or radiation had been used. Some diagnoses were only confirmed by x-ray and not acceptable to the commission. Reportedly, several doctors “denied their previous diagnoses”. The commission concluded that of the eight patients with a confirmed diagnosis, two of the four recoveries could be attributed to essiac⁵.

Following years of controversy and litigation, Caisse closed her clinic in 1942. It is not clear whether any patients were treated during the following years, but she continued to receive requests for treatment. In 1958, the Royal Cancer Commission again asked that she release the ingredients of her formula, but she refused saying that she had not been assured that it would be used to treat patients with cancer^2,5.

In 1959, Caisse was invited by the Science Research Institute of New York to collaborate with Drs. Charles Brusch and Charles McClure in their Cambridge, Massachusetts, clinic. Dr. Brusch encouraged her to have her essiac formula tested on mice in addition to patients. Mice were provided by and subsequently autopsied at Memorial-Sloan Kettering in a study that was never published. In order to do further testing, Memorial-Sloan Kettering requested the formula, but Caisse again refused. A request from the National Cancer Institute was also refused^2,5.

From 1973 until 1976, Caisse again provided Sloan-Kettering (Dr. Chester Stock) with essiac material and instructions for preparation for testing in mice. Disappointing results led to accusations of improperly prepared essiac and the implantation of animal rather than human carcinoma in the mice⁵. According toThe Essiac Report, the material which she had provided was 25 years old and only included one previously injectable herb².

In 1977, Caisse and Brusch entered into an agreement for Resperin Corporation to produce and supply Essiac® for a clinical trial in terminal cancer patients under the guidelines of the Canadian Health Protection Branch of the Department of Health and Welfare. The trial began in 1978, but disagreements soon developed concerning the use of conventional treatment along with essiac and Rene Caisse died that same year. The trial was closed in 1982 by the Health Protection Branch which cited inadequate manufacturing controls for consistency in batches plus a poorly conceived and executed study design. Canadians were allowed to obtain Essiac® under the Emergency Drug Release Act, but this required official requests through their physicians^1,2.

In 1984, Elaine Alexander, a radio talk show host and producer in Vancouver, British Columbia, interviewed Dr. Brusch. Renewed public interest resulted in many requests by patients with cancer for assistance in navigating government processes to obtain Essiac®. Alexander and Brusch decided that they could bypass government regulations by promoting essiac as a health tonic with no claims as a cancer cure so that individuals could obtain it directly. Their brand, known as Flor*Essence®, contains four additional herbs².

In 2004, the first in vitro studies were finally published in the peer-reviewed scientific literature^16,17 and are described in the Summary of Research.

Herbs in Essiac Formulas

The question of which herbs were used in the original essiac formula has a complicated history. Some references say that the original formula that Caisse obtained from an Ojibwa source consisted of four herbs: burdock root, slippery elm bark, sheep sorrel and Turkish rhubarb. (According to one herbal authority, two of these herbs, sheep sorrel and turkish rhubarb, have no recorded use by native peoples of North America.) Others insist that the original formula had eight herbs that Caisse reduced to four and then returned to the original eight by adding watercress, blessed thistle, red clover and kelp¹. [Comment by Ed.-NR: One wonders why kelp would have been part of the original formula, since the Ojibwa people lived in the region of the Great Lakes and kelp is a seaweed that grows off the coast of western North America.]

Proposed Mechanism of Action

The four to eight herbs in essiac formulas have traditionally been viewed in folklore as cleansing and strengthening. Two sets of reviews of the mechanisms of action of the individual herbs as demonstrated by animal and in vitro studies are available. One set from the collaborative review organization, Natural Standard, includes burdock, blessed thistle and red clover. Another set funded by the National Center for Complementary/Alternative Medicine and the National Cancer Institute includes these three plus the remaining herbs (slippery elm, sheep sorrel, Turkish rhubarb, kelp and watercress) as summarized in a table(pdf) adapted from the article. Both sets of reviews report some evidence of estrogenic, antioxidant, antiinflammatory, antimicrobial and anticarcinogenic activities. However, they also caution against exceeding recommended doses or use during pregnancy or with diabetes.

Adequacy of Doses

Although some therapeutic actions have been reported for specific herbs within essiac tonics, it is unknown whether the doses in these tonics are sufficient to be effective due to the proprietary (secret) nature of their formulas. John Boik, MAcOM, has estimated percentages for four herbs and concluded that their potential doses are relatively small compared with common medicinal doses. His estimated percentages are summarized in a table, Daily Dose of Constituent Herbs in Various Essiac-like Formulas.

Synergistic effects of combinations of essiac herbs are theroretically possible, but have not been described in the scientific literature.

Standardization

The University of British Columbia in vitro study compared three different lots each of Essiac® (ES) and Flor*Essence® and confirmed consistency through high performance liquid chromatography (HPLC)¹⁷.

Toxicity and Interactions

A 1978 report of burdock root tea poisoning was determined to be due to an atropine alkaloid contaminant of a commercial tea due to contamination with another herb (belladona) during harvesting^7,8. Three cases of allergic contact dermatitis have been reported following the use of burdock plaster for 12 hours, six days and seven days⁹.

A 1998 literature review by the Task Force on Alternative Therapies of the Canadian Breast Cancer Research Initiative did not identify any adverse effects from essiac tea. That review, however, cautioned that individual herbs might be associated with allergic dermatitis and noted laxative effects along with the previously reported burdock contamination with atropine¹⁰.

A 1999 presentation of an abstract at the American Society for Clinical Oncology (ASCO) reported reduced clearance of chemotherapy in a woman who was drinking essiac tea. This resulted in toxicity (neutropenia and thrombocytopenia) from the chemotherapy¹¹.

A survey of North American consumers published in 2000, reported adverse gastrointestinal effects and fatigue, but these effects were only reported by those who had taken higher than recommended doses¹².

Summary of Research

Amount and Type of Research

Based on our review of the literature and other sources searching for the keyword “essiac” and cancer or other neoplastic and anti-neoplastic terms, we identified and retrieved eight articles providing new information between May 2005 and April 2006.

Previous searches had identified two articles published between 9/1/2002 and 5/20/2005 and 10 articles published between 10/31/1997 and 8/31/2002. 

The initial search and review of the literature prior to 10/31/1997 identified 125 references, of which 74 (59%) were applicable to cancer. Combining the results of these four reviews yields 94 articles applicable to essiac and cancer. Of these, we have retrieved 65 (69%) and classified these references into the following types of information:

Of the human related articles, we coded the studies (3) by the following study designs:

Note: Several additional sets of case reports and testimonials have been identified^2,5,13,14,15, but these are not included in this table because of missing information and/or lack of independent verification.

Summary of Human Research

Presentations of cases to the Canadian Royal Cancer Commission⁵ are not available in the Canadian archives¹. Under the guidelines of the Canadian Health Protection Branch of the Canadian Department of Health and Welfare, a clinical trial was started in 1978 for terminal cancer patients, but never completed¹.

In the early 1980s, the Canadian Bureau of Human Prescription Drugs conducted a retrospective review of Caisse’s patients based on summaries voluntarily submitted by their physicians. One hundred fifty physicians submitted information on 86 patients, all of whom had previously received conventional therapy. Positive responses among the 86 patients were that one showed subjective improvement, five required fewer analgesics and three remained stable¹.

A survey of North American consumers of the Flor-essence® brand of essiac was published in 2000. It reported a 6.4% response rate with 50.6% of respondents reporting improvement in symptoms. Among the 6.6% who reported adverse events of nausea, vomiting and diarrhea, 11.8% had exceeded the daily recommended dose¹².

Two case reports have been published in the peer-reviewed literature. One case report of reduced clearance of chemotherapy¹¹ has been discussed earlier within the section for toxicity. The role of essiac in this case is suspect, but not definitive. The other case report concerned a man with hormone-refractory prostate cancer who experienced a dramatic drop in his PSA after he began drinking essiac tea. He then discontinued his hormone treatment, but his PSA remained low as of the publication of the report five years later¹⁸.

According to various sites on the Internet, two clinical trials have been conducted in China, but searches of the English and Chinese literature by the Interlibrary Loan Service have not been able to locate any published articles concerning these studies.

In 1998, the Task Force on Alternative Therapies of the Canadian Breast Cancer Research Initiative reviewed the literature on Essiac. The task force was not able to identify any published laboratory or human clinical trials so they reviewed unpublished laboratory studies and personal testimonials. They concluded that all information reviewed for Essiac “reveals some weak evidence of its effectiveness and suggests that Essiac is unlikely to cause serious side effects when used as directed.”¹⁰

A “trial of essiac” in women with breast cancer was presented as an abstract at a symposium in Exeter, UK, but it is actually a retrospective survey that is still in process¹⁹.

Summary of in Vitro Research

Five in vitro studies have been identified that have addressed effects upon proliferation of cells, oxidation and immune system components.

Dose-dependent decreases in cellular proliferation have been reported in two studies. Ottenweller and colleagues at Indiana University reported that 5-10% solutions of Essiac® decreased proliferation of human prostate cancer cells¹⁶. Tai and colleagues at the University of British Columbia compared the effects on breast cancer cell lines of four substances: Essiac® (ES), Flor-Essence® and two standard herbal derived chemotherapies (camptothecin and pacletaxel).  They reported that both herbal teas showed “weak” antiproliferative effects compared with the chemotherapies, with Essiac® showing lower activity than Flor-essence®¹⁷. 

In contrast, Kulp and colleagues found that Flor-Essence® and Essiac® at 1%, 2%, 4% and 8% solutions stimulated proliferation in both ER+ and ER- breast cancer cell lines. However, higher concentrations (16-32%) of the tea decreased or did not affect the growth of these cells²⁰. [Comment by Ed.-JB: Cells that are completely depleted of estrogen do not mimic in vivo conditions. In such cases, a weak estrogen could stimulate cell growth. In the presence of estrogen, however, the natural compounds might compete for binding sites and thus reduce the stimulatory effects of endogenous estrogen.]

Antioxidant activity and immune effects have been addressed in three studies. Cheung and colleagues found that Essiac® and Flor-essence® had different effects upon mouse macrophage cells. Essiac® dose-dependently induced nitrous oxide (NO) production in cells, but inhibited its production when those cells had been previously stimulated with a lipopolysaccharide. In contrast, Flor-essence® did not stimulate NO production in cells and did not inhibit its production in cells stimulated with lipopoysaccharide. Neither Essiac® nor Flor-essence® stimulated messenger RNA expression of the pro-inflammatory mediators IL-1B, iNOS and COX-2. Neither tea stimulated nor modulated inflammatory activity in lipopolysaccharide stimulated cells and these teas had no effect upon production of the cytokine, TNF-a . That is, neither herbal formula had anti-inflammatory activity²¹. Leonard and colleagues at the National Institute for Occupational Safety and Health evaluated Essiac® tea in mouse monocyte cells at 5, 10, 25 and 50% solutions. They reported that Essiac® effectively scavenged hydroxyl and oxygen radicals, inhibited lipid peroxidation and prevented DNA damage caused by hydroxyl radicals²². Ottenweller’s previously described study on cellular proliferation also reported that essiac tea stimulated normal mouse spleen cell derived T-cells¹⁶.

Doses used in these studies have generally been higher than what would be recommended or even achievable in animals or humans. Biologically available plasma doses of oral Essiac® and Flor-Essence®  are currently unknown²¹.

Notes concerning testimonials

Testimonials are not included within this Summary of Research due to problems with lack of complete documentation and independent verification. Readers are advised to consider the excellent discussion of the problems with testimonials, inCancer Guides, Judging Essiac Testimonials and Recovery Stories.

Brief notes about published studies are contained within the Table of Essiac Human Studies.

Study descriptions and sources for these data are available in the Annotated Bibliography.

Annotated Bibliography 

Human Studies

¹Office of Technology Assessment (OTA). Essiac. Unconventional Cancer Treatments: A Report of the Office of Technology Assessment to the United States Congress. Washington, D.C.: US Government Printing Office, 1990. Report No.: Reprinted by the Commonweal Research Institute. Also available online.

Purpose: Survival/ cancer regression
Type of Study: Retrospective review
Methods: The Canadian bureau requested case summaries from 150 physicians who had reportedly requested Essiac on behalf of their patients. Original chart reviews were not done.
Results: “Approximately half” of the physicians submitted summaries for 86 patients. The bureau summarized the outcomes as follows:

• 47 – no benefit
• 8 – unevaluable
• 17 – died
• 1 – subjective improvement
• 5 – required fewer analgesics
• 4 – objective response
• 4 – stable condition

¹²Richardson MA, Ramirez T, Tamayo C, Perez C, Palmer JL. Flor-Essence Herbal tonic use in North America. Herbalgram 2000;50:40-6.

Purpose: Determine pattern of use and perceived benefits or adverse events
Type of Study: Survey
Methods: Cards were attached to each box of herbs or bottle of Flor*Essence tonic shipped in Canada and the United States over a three-month period beginning in June of 1998. These cards invited purchasers to participate in a study between June of 1998 and August of 1999. Returned cards provided information on demographics, reasons for use, duration of use and perceived benefits along with a unique identification number for confidentiality. In addition, current or former cancer patients were invited to call the study center to inquire about the details of a second survey specifically about their experience with the tonic. The manufacturer, Flora Manufacturing and Distributing Ltd., provided one complimentary product to each of those who completed the cancer-specific summary.
Results:

Response Rates - Of 85,245 products distributed, 5,435 (6.4%) were returned, but 384 were excluded because they were treating pets or replied after the study had closed. Of the remaining eligible respondents, 3,749 (74.2%) were cancer patients and 54.9% (n=2,060) consented to participate and 1,588 (42.4%) completed the study (1,577 before the close of the study).
Characteristics of Respondents -The majority of consumers were educated above high school (63.3%), Caucasian, married, living in the U. S., an average of 61.6 years of age and approximately even by gender. Demographic data were unavailable for 366 patients with cancer. Most patients with cancer (85.3%) had received previous cancer treatment including surgery, chemotherapy, radiation, hormones or other and 36.8% were receiving current treatment.
Perceived Benefits - Most rated the benefits from good/excellent (71.05) and OK (27.1%) to not very good/poor (2.8%). Positive effects included feeling better (53.2%), no cancer progression (40.6%), able to carry out daily activities (34.0%), more energy (31.5%), coping better with the disease (26.3%), improved cancer symptoms (22.3%) and “cured their cancer” (16.2%). Improvements were reported in fatigue (29.8%), appetite loss (15.0%), nausea (8.4%), pain (11.65), vomiting (4.1%) and other symptoms (12.4%).
Adverse Effects - Ill effects reported included diarrhea (1.9%), constipation (1.2%), nausea (1.1%) and fatigue (0.9%). However, of the 6.6% of respondents with adverse effects, 11.8% said that they had exceeded the recommended daily dose.

¹¹Geyer C, Hammond L, Johnson T, et al. Dose-schedule optimization the hexacyclic camptothecin (CPT) analog DX-8951f: a phase I and pharmacokinetic study with escalation of both treatment duration and dose (meeting abstract). Proc Ann Meet Am Soc Clin Oncol 1999;A813.

¹⁸Al-Sukhni W, Grunbaum A, Fleshner N. Remission of hormone-refractory prostate cancer attributed to Essiac. Canadian J Urology 2005;12(5):2841-2.

Purpose: Effect on PSA levels
Type of Study: Case report
Methods and results: (Prostate) A patient with T1cN0M0 (local, stage 1) prostate cancer had an androgen (PSA) level of 46.6 ng/ml and Gleason score of 9/10 bilaterally. He was treated with primary androgen deprivation therapy, and, after four months, his PSA had fallen to 0.60 ng/ml where it remained for about four months, but then began to rise reaching 87.19 ng/ml by 21 months after the start of hormone therapy. The patient then began to supplement his hormone therapy by drinking essiac tea twice daily. Four months later, his PSA had fallen to 0.12 ng/ml. His PSA rose slightly to 3.21. The hormone therapy was then withdrawn and his PSA level fell to 0.16 ng/ml and then remained at 1.7 for the next three years when the report was submitted.

In Vitro Studies

¹⁶Ottenweller J, Putt K, Blumenthal EJ, Dhawale S, Dhawale SW. Inhibition of prostate cancer-cell proliferation by Essiac. The Journal of Alternative and Complementary Medicine 2004;10(4):687-91.

¹⁷Tai J, Cheung S, Wong S, Lowe C. In vitro comparison of Essiac® and Flor-essence® on human tumor cell lines. Oncology Reports 2004;11:471-6.

²¹Cheung S, Lim K-T, Tai J. Antioxidant and anti-inflammatory properties of ESSIAC and Flor-Essence. Oncology Reports 2005;14:1345-50.

Purpose: Evaluation of antioxidant and immune effects
Type of Study: In vitro
Methods:Three different lots of Essiac®  in powdered form and three different lots of Flor-essence® in liquid form were purchased from natural health food stores in Vancouver, British Columbia, Canada. Teas were prepared according to manufacturers’ instructions and then diluted and mixed with culture mediums for the RAW 264.7 mouse macrophage / monocyte cell line. (Additional details provided in article.)
Results:

Antioxidant activity: Essiac® dose-dependently induced nitrous oxide (NO) production in cells, but inhibited its production when the cells were stimulated with lipopolysaccharides. In contrast, Flor-essence® did not stimulate NO production in cells and did not inhibit its production when the cells were stimulated with lipopolysaccharides.
Inflammatory activity: Essiac®  and Flor-essence® both significantly induced the pro-inflammatory cytokines, IL-1B, iNOS and COX-2 mRNA expression to more than double that of controls. However, in lipopoysaccharide stimulated cells, neither tea had any effect upon mRNA expression of these cytokines.

²²Leonard SS, Keil D, Mehlman T, Proper S, Shi X, Harris GK. Essiac tea: Scavenging of reactive oxygen species and effects on DNA damage. J of Ethnopharmacology 2006;103:288-96.

Purpose: Evaluation of antioxidant effects
Type of Study: In vitro
Methods: Essiac® in powder form was added to distilled water, boiled for 10 minutes, left to cool for four hours and then boiled for another five minutes. Both filtered and unfiltered extracts of the tea were then used in doses ranging from 5 to 50%. Electron spin resonance (ESR) trapping was used to detect free radical generation in cultured mouse monocyte cells. Lipid peroxidation (an indicator of possible free radical damage) was estimated with colorimetric assays of varying doses of Essiac® mixed with iron sulfate and hydrogen peroxide (Fenton reaction). DNA damage was assayed by counting strand breaks as determined through electrophoresis and photography of gels. (Details provided in article.)
Results:

1. Both filtered and unfiltered extracts of Essiac® scavenged hydroxyl radicals from the Fenton reaction in a concentration dependent manner.
2. Both filtered and unfiltered extracts of Essiac® reduced the superoxide radicals generated by a xanthin/xanthine oxidase system and measured using ESR.
3. Increasing concentrations of filtered Essiac® reduced radicals generated by chromium stimulated cells as measured by ESR.
4. Filtered Essiac® protected cells from hydroxyl radical induced lipid peroxidation generated by the Fenton reaction in a concentration-dependent manner.
5. Filtered Essiac® also protected DNA from the fragmenting effects of these hydroxyl radicals.

²⁰Kulp KS, Montgomery JL, Nelson DO, Cutter B, Latham ER, Shattuck DL, et al. Essiac®  and Flor-Essence®  herbal tonics stimulate the in vitro growth of human breast cancer cells. Breast Cancer Research and Treatment 2006 Mar;1-11.

Purpose: Effects upon cellular proliferation
Type of Study: In vitro
Methods: Essiac® tea was obtained from a local health food store as a powder and prepared as recommended by the manufacturer. Flor-Essence® tea was also obtained at a local health food store, but as a previously prepared liguid. Both preparations were used in concentrations varying from 1 to 32%. Four human breast cancer cell lines that were estrogen receptor (ER) positive and negative were placed in a cell culture plate containing 96 wells. Different concentrations of the two teas or genistein or sterile water were then added to the different wells and evaluated at 24 and 72 hours. All experiments were repeated more than four times. 
Results: Flor-Essence® treatment was associated with a significant increase in cell proliferation from 1.5-fold to 2.1-fold (P<0.001) in all cell lines at 24 hours, regardless of ER status and activated ER dependent transcription. Because both tonics were able to stimulate growth in both ER+ and ER- cell types, the authors postulated that non-estrogenic pathways must have been activated. They tested for such pathways by specifically blocking the estradiol-binding site on the ER receptor and found that this did not affect cell proliferation. Incubation of the cells with the two herbal tonics for 72 hours yielded increased and continuous cell proliferation. Although there was little difference between the two tonics on cell proliferation, Flor-essence®, the tea with additional herbs, tended to produce a greater response in the ER+ cell lines.

Full citations are provided in the Reference List

Reference List

1. Office of Technology Assessment (OTA). Essiac. Unconventional Cancer Treatments: A Report of the Office of Technology Assessment to the United States Congress. Washington, D.C.: US Government Printing Office, 1990. Report No.: Reprinted by the Commonweal Research Institute. Also available in the online OTA archives. (Maintained by Princeton University.)
2. Thomas R. The Essiac Report: The True Story of a Canadian Herbal Cancer Remedy and of the Thousands of Lives it Continues to Save. 3rd ed. Los Angeles, CA: Alternative Treatment Information Network, 1993.
3. Low Dog T. Author of CME article offers clarification about essiac. Alternative Therapies in Health and Medicine 2001;7(4):20.
4. Harris A. Research and Scientific Studies about Essiac [Web Page]. (Accessed 1910 Mar 2).
5. Fraser SS, Allen C. Could Essiac Halt Cancer? Homemaker’s Magazine 1977;June /July/ August:1-18.
6. Tamayo C, Richardson MA, Diamond S, Skoda I. The chemistry and biological activity of herbs used in flor-essence herbal tonic and essiac. Phytotherapy Research.14. 2000;14(1):1-14.
7. Bryson PD, Watanabe AS, Rumack BH, Murphy RC. Burdock root tea poisoning. Case report involving a commercial preparation. JAMA 1978 May;239(20):2157.
8. Rhoads PM, Tong TG, Banner W Jr, Anderson R. Anticholinergic poisonings associated with commercial burdock root tea. Journal of Toxicology – Clinical Toxicology 1984;22(6):581-4.
9. Rodriguez P. Blanco J. Juste S. Garces M. Perez R. Alonso L. Marcos M. Allergic contact dermatitis due to burdock (Arctium lappa). Contact Dermatitis 1995;33(2):134-5.
10. Kaegi E. Unconventional therapies for cancer: 1. Essiac. Canadian Medical Association Journal 1998;158(7):897-902.
11. Geyer C, Hammond L, Johnson T et al. Dose-schedule optimization the hexacyclic camptothecin (CPT) analog DX-8951f: a phase I and pharmacokinetic study with escalation of both treatment duration and dose (meeting abstract). Proc Ann Meet Am Soc Clin Oncol 1999;A813.
12. Richardson MA, Ramirez T, Tamayo C, Perez C, Palmer JL. Flor-Essence Herbal tonic use in North America. Herbalgram 2000;50:40-6.
13. Ko Marne. Back from the brink. Report Magazine. British Columbia, Canada: 2000:36-9.
14. Essiac International Literature. Testimonials.1996 Mar.
15. Various authors. Essiac Testimonials from the Internet.1996 Mar.
16. Ottenweller J, Putt K, Blumenthal EJ, Dhawale S, Dhawale SW. Inhibition of prostate cancer-cell proliferation by Essiac. The Journal of Alternative and Complementary Medicine 2004;10(4):687-91.
17. Tai J, Cheung S, Wong S, Lowe C. In vitro comparison of Essiac and Flor-essence on human tumor cell lines. Oncology Reports 2004;11:471-6.
18. Al-Sukhni W, Grunbaum A, Fleshner N. Remission of hormone-refractory prostate cancer attributed to Essiac. Canadian J Urology 2005;12(5):2841-2.
19. Boon H, Zick S, Green J, Olatunde S. Trial of Essiac to ascertain its effect in women with breast cancer (FACT). Focus on Alternative and Complementary Therapies 2005;10(Supplement 1):6.
20. Kulp KS, Montgomery JL, Nelson DO, Cutter B, Latham ER, Shattuck DL,et al. Essiac®  and Flor-Essence®  herbal tonics stimulate the in vitro growth of human breast cancer cells. Breast Cancer Research and Treatment 2006 Mar;1-11.
21. Cheung S, Lim K-T, Tai J. Antioxidant and anti-inflammatory properties of ESSIAC and Flor-Essence. Oncology Reports 2005;14:1345-50.
22. Leonard SS, Keil D, Mehlman T, Proper S, Shi X, Harris GK. Essiac tea: Scavenging of reactive oxygen species and effects on DNA damage. J of Ethnopharmacology 2006;103:288-96.

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