Gerson therapy

The Gerson therapy uses a special diet, supplements and also coffee enemas to detoxify and stimulate the body’s metabolism. Proponents of the Gerson therapy have made claims that it is an effective treatment for cancer and other illnesses, through balancing the levels of potassium and sodium in the body, removal of toxins and regeneration of liver function and also improving overall nutritional status.

Based on one methodologically flawed retrospective study and several case reports, there is no clear evidence that Gerson therapy is an effective treatment for people with cancer. A small best case series review concluded that both physical and psychological benefits, appeared to be offered by this regime, but these findings have not been replicated in any acceptable trials. Some evidence exists to suggest that elements of the therapy (coffee enemas in particular) are potentially dangerous if used excessively. In addition to this the excessive demands of time, money and other resources on the patient undergoing the therapy may be extreme. An indirect risk is that patients following Gerson therapy are advised to cease conventional cancer treatments including chemo-or radiotherapy.


Helen Cooke, Helen Seers, CAM-Cancer Consortium. Gerson therapy [online document], August 25, 2020.

Document history

Latest update: September 2020

Next update due: September 2023


The Gerson therapy uses a special diet, supplements and also coffee enemas to detoxify and stimulate the body’s metabolism.


Originally devised by Dr. Max Gerson (a German doctor 1881-1959), the Gerson approach is now headed by his daughter Charlotte Gerson, who presently leads the Gerson Institute in the United States (US). The Gerson Institute is linked to the “Baja Nutri Care Clinic” in Tijuana, Mexico and a Hungarian clinic, which have both been licensed to practice the therapy by the Gerson institute. To publicise the therapy as much as possible, Charlotte Gerson tours the world lecturing and providing workshops for patients and health care professionals1.


The Gerson diet is entirely organic and vegetarian and includes up to 13 glasses of fresh juices a day. Coffee enemas are administered (up to five a day) as they are believed to stimulate the toxin-removal activity of the bile ducts, liver, and bowel. A variety of supplements may also be administered on the Gerson regime, these include: potassium compound, Lugol’s solution (an inorganic solution of iodine with potassium iodide), thyroid hormones, vitamin B12 and pancreatic enzymes1.

Application and dosage

Treatment is initially provided by Gerson clinics. Until recently, the only medical facility licensed by the Gerson Institute was the Baja Nutri Care Clinic, located in the Playas area of Tijuana, Mexico. There is now also a clinic in Hungary that has also been licensed by the Gerson Institute1. Charlotte Gerson and the Gerson Institute staff visit the clinic on a regular basis. The Gerson Institute supplies support and advice to anyone wishing to carry out the therapy at home.

The Gerson Institute provides a newsletter and contact details of support groups run by long-term recovered patients. The Gerson Institute offers a list of “Recovered Patient Referrals” to prospective new patients. Further details of the Gerson network are set out on their website1.

Claims of efficacy/mechanism(s) of action/alleged indications

The intensive treatment based on nutrition and detoxification is claimed to restore and revitalise the body, strengthen the immune, enzyme and hormone systems and correct the function of the essential organs. The Gerson therapy is not targeted at any one specific symptom or disease, instead it is claimed to treat the underlying cause of the disease, therefore restoring health to the whole body. By supplying nutrients that are thought to be “easily absorbed” and utilized by the body it is thought that this provides the optimum conditions for healing. After restoring the body with “hypernutrition” it is believed that excess sodium and toxins (due to previous poor nutrition and exposure to environmental pollution) are released. With the release of toxins into the system it is according to the Gerson approach necessary to support the liver in removing these damaging by-products.

Importantly, the Gerson therapy is supposed to be an alternative therapy, it does not encourage the use of chemotherapy alongside its regime. This is because it is believed that those undergoing chemotherapy prior to Gerson therapy have an immunological disadvantage. The use of radiotherapy is considered more compatible with Gerson therapy2.

One published review of the therapy found that the theoretical rationale behind the Gerson therapy does not stand up to scrutiny3.

Prevalence of use

Reliable estimates of how many people follow the therapy worldwide are not available.

Legal issues

There are two Gerson treatment centres licensed by the Gerson Institute in the world (one in Mexico and one in Hungary).The Gerson Institute offers training to a variety of different health practitioners to enable people to become licensed Gerson Practitioners.


The treatment at the Mexico clinic costs $5,500 per week (the cost is 5,500 Euro in Hungary) and usually lasts around two to three weeks4,5. The weekly fee is inclusive of accommodation, meals and treatment. People are encouraged to continue the therapy for approximately two years at home. This involves ongoing expense including regular telephone consultations with a private physician, juicing equipment, large quantities of organic vegetables and the cost of supplements. In total the Gerson therapy consumes large amounts of time, money and other resources and only dedicated individuals will be able to stick to the demands of the therapy.

Based on one methodologically flawed retrospective study and several case reports, there is no clear evidence that Gerson therapy is an effective treatment for people with cancer. A small ‘Best Case Series’ review concluded that both physical and psychological benefits, appeared to be offered by this regime, but these findings have not been replicated in any acceptable trials. No randomised controlled trials have been conducted on the Gerson Therapy. Attempts to evaluate the Gerson therapy as a whole are problematic due to the complexity of the treatment, time taken for its possible effectiveness and poor record keeping/tracking of previous patients by the Gerson Institute6.

Clinical trials

A five-year survival rate retrospective study of 153 cancer patients found higher survival rates in patients with melanoma, colorectal and ovarian cancers undergoing the Gerson regime than for patients undergoing other therapies7. However, it should be noted this work was conducted by members of the Gerson Research Organisation and has been criticised as being seriously methodologically flawed8. This research did not use the same matched control for each of their categories studied. Furthermore, it was not performed under tightly controlled conditions assessing the other therapies that the patients may have been receiving.

Case reports/series

Since the 1940s several attempts have been made to assess the efficacy of the Gerson therapy. In 1947 the NCI (National Cancer Institute) reviewed case studies of ten people from Gerson and found no evidence to support Gerson’s claims of the therapy being effective.9 The 50 cases presented in Gerson’s 1958 book10 were also reviewed by the NCI in 1959, however, it was concluded that the case histories were not presented in sufficient detail (for instance, verification of the tumour, previous treatment history) to be able to evaluate the clinical benefit of the therapy11.

A preliminary study conducted in 1983 tracked down 21 patients over a five-year period and found all but one (who was not cancer free) had died at the end of the study period12. However, due to not obtaining detailed medical records at the start of this study this research is not very substantive.

In 1989, Reed et al. visited the Gerson clinic to evaluate the efficacy of the therapy on behalf of a British medical insurance company13. Two investigations were conducted and presented in one paper. The first investigation concerned how patients responded to the therapy and the other was a psychological study of the patients at the clinic. For the first investigation, the Gerson clinic presented 149 cases to the researchers. Of the 149 only 27 cases were able to be assessed as they possessed independent documentation of their disease from a mainstream physician. The researchers concluded that there was little evidence for the Gerson therapy having an anti-tumour effect, instead finding only a very small amount of successful responses with three of the 27 cases showing a complete response and one patient with a stable disease result. The second study by Reed et al collected data from 15 patients concerning their psychological state while undergoing the therapy13. The researchers found a marked enhancement of pain control and quality of life was enhanced. However, it must be noted that no firm conclusions can be drawn from this observational study due to the small number of participants.

A 2007 case study analysis of six people with cancer who followed the Gerson therapy concluded that some support, both physical and psychological, appeared to be offered by this regime14. The analysis reported that some potential anti-cancer effects appeared to be present in the patients who undertook this regime. The patients also had an increased sense of hope and empowerment. The authors stated however that many cofactors may have influenced these findings; some of the patients were undergoing conventional treatment, some were also using other complementary approaches. The analysis was conducted using the 'Best Case Series' criteria developed by the National Cancer Institute15.

A 2010 overview of the Gerson regimen reported that case reviews by the National Cancer Institute (NCI) and the New York County Medical Society found no evidence of usefulness for the Gerson diet16.

There is concern that people may choose to use this regime as an alternative to chemotherapy, thereby avoiding mainstream treatment. The Gerson Institute does not recommend the use of chemotherapy with the diet since the chemotherapy is seen as a poison in the body, and during detoxification the body would find difficulty in dealing with the level of toxins1. Several aspects of the Gerson therapy itself have been seen as possible causes of adverse effects. These include: coffee enemas17, the restrictive nature of the diet, thyroid supplements and also the now disused practice of drinking liver juice. The American Cancer Society and the US National Cancer Institute, do not recommend the use of the Gerson therapy, warning that patients should not turn away from mainstream therapy to rely only on this alternative approach.

Adverse effects

Coffee enemas

Serious illnesses, colitis, electrolyte imbalance and even death have been associated with the use of coffee enemas17. However, these incidences have not been reported in patients undergoing the Gerson treatment at the clinic. In two isolated cases reported two women in Seattle (one with cancer) died due to the enemas removing potassium from the body leading to serious electrolyte imbalance. In either case enemas were used more frequently than is recommended by the Gerson therapy guidelines. It is thought that continued home use of enemas may weaken the colon’s natural function leading to problems such as constipation and colitis17.

Restricted diet

The use of a restricted detoxifying metabolic diet alongside enemas may cause an “inflammatory reaction” which is believed to be part of the healing process.10 Negative symptoms of this inflammatory reaction include dehydration, nausea, diarrhoea, flu-like symptoms and death18.


There are safety concerns over the excessive ingestion of potassium. Those with too much potassium in their blood may suffer from hyperkalemia; symptoms include muscle numbness, tingling, abnormal heart rhythm, paralysis and possible heart failure19.

Calves liver juice

The drinking of calves’ liver juice was removed from the Gerson therapy guidelines in 1989 after a history of it being associated with infection with Campylobacter fetus subspecies fetus20. An outbreak of this bacterial infection was seen in 1981 which killed nine cancer patients who were thought to be using the Gerson treatment20,21. After learning of this outbreak staff at the Gerson Institute worked with those at the clinic in Mexico to ensure patient safety and by 1989 the policy of drinking liver juice was altered to receiving crude liver extract injections.


Due to the complex nature of the therapy many interactions with other drugs may occur.


The National Cancer Institute22 urges patients to not seek treatment from the Gerson clinic due to a lack of evidence of the anti-cancer effects and also potential hazards associated with the therapy.

  1. Gerson Institute Homepage [available online]. 2017. Accessed 8th of September 2020.
  2. Gerson, C & Walker, M. The Gerson Therapy. 60 years of proven success! Kensington Publishing, USA; 2001.
  3. Green S. A critique of the rationale for cancer treatment with coffee enemas and diet. JAMA. 1992; 268: 3224-3227. Accessed 8th of September 2020.
  4. Revill, J. Now Charles backs coffee cure for cancer, Observer, June 27 2004. Accessed 8th of September 2020.
  5. Personal communication with H. Strauss, representative of the Gerson Institute, 16th August 2004.
  6. Moss RW, Moss RW. Patient perspectives: Tijuana cancer clinics in the post-NAFTA era. Integrative Cancer Therapies. [Historical Article]. 2005 Mar;4(1):65-86. Accessed 8th of September 2020.
  7. Lowell, J. The Gerson Clinic. Nutrition Forum. 1986; 3(2):9-12.
  8. Hildenbrand, GL, Hildenbrand, LC, Bradford, K, & Cavin, SW. Five-year survival rates of melanoma patients treated by diet therapy after the manner of Gerson: a retrospective review. Altern Ther Health Med. 1995; 1:29-37. Accessed 8th of September 2020.
  9. Ernst, E. The Desktop Guide to Complementary and Alternative Medicine: An Evidence-Based Approach, Mosby, London; 2001.
  10. U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health, National Cancer Institute, National Cancer Institute Statement, "Unproven Methods: The Gerson Therapy," February 5, 1987.
  11. Gerson, M. A Cancer Therapy. Results of Fifty Cases, 6th Ed. Bonita, CA: Gerson Institute, 1999.
  12. Avery, RJ, Office of Cancer Communications, National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services, letter to G. Dego, University of London, August 24, 1982.
  13. Austin, S, Dale, EB, & DeKadt, S. Long-term follow-up of cancer patients using Contreras, Hoxsey and Gerson therapies. Journal of Naturopathic Medicine. 1994; 5(1):74-76
  14. Reed A, James, N, & Sikora, K. Mexico: juices, coffee enemas, and cancer. Lancet, 1990; 336 (8716):677-678. Accessed 8th of September 2020.
  15. Molassiotis A, Peat P. Surviving against all odds: analysis of 6 case studies of patients with cancer who followed the Gerson therapy. Integrative Cancer Therapies. [Case Reports]. 2007 Mar;6(1):80-8. Accessed 8th of September 2020.
  16. Cassileth B. Gerson regimen. Oncology (Williston Part) 2010; 24(20): 201.
  17. Eisele, JW, & Reay, DT. Deaths related to coffee enemas, JAMA. 1980; 244: 1608-9.
  18. Anonymous. Questionable methods of cancer management: 'nutritional' therapies. CA Cancer J Clin. 1993; 43(5):309-19. Accessed 8th of September 2020.
  19. Tobian, L. Dietary sodium chloride and potassium have effects on the pathophysiology of hypertension in humans and animals. American Journal of Clinical Nutrition. 1997; 65: S606- S611.
  20. Gerson Institute, "Raw Liver Juice Has Been Discontinued," Memo, October 3 1989.
  21. Ginsberg, MM, Thompson, MA, Peter CR, et al., "Campylobacter Sepsis Associated With 'Nutritional Therapy'--California," M.M.W.R. 1981; 30(24): 294-295.
  22. National Cancer Institute. Gerson Therapy PDQ. Available online. Accessed 8th of September 2020.

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