+ -Text Size

Metabolic Therapy

Other common name(s): Kelley's treatment, Gonzalez treatment, Issels whole body therapy, Gerson therapy

Scientific/medical name(s): none


Metabolic therapy uses a combination of special diets, enzymes, nutritional supplements, and other measures in an attempt to remove "toxins" from the body and strengthen the body's defenses against disease.


There is no convincing scientific evidence that metabolic therapy is effective in treating cancer. However there are many different practices that make up metabolic therapy. Some of these practices may be harmful.

How is it promoted for use?

Metabolic therapy is based on the belief that toxic substances in food and the environment build up in the body and create chemical imbalances that lead to diseases such as cancer, arthritis, and multiple sclerosis. Some proponents of this approach say that metabolic therapy rids the body of these toxins and strengthens its resistance to disease. Some claim that a special diet can cure serious illnesses, including cancer. Others claim that they can evaluate a patient's metabolism and diagnose cancer before symptoms appear and that they can locate tumors and learn the tumor's size and growth rate.

What does it involve?

Metabolic therapies vary a great deal depending on the practitioner, but all are based on special diets and detoxification. This usually involves natural, whole foods such as fresh fruits and vegetables, as well as vitamins and mineral supplements. Other measures may include colonic irrigation with coffee or hydrogen peroxide enemas, juicing, enzyme supplements, visualization, and stress-reduction exercises. At least one metabolic therapy system also includes the drug laetrile (see Colon Therapy, Enzyme Therapy, Imagery, Juicing, and Laetrile).

Among the better known types of metabolic therapy are Kelley's treatment, the Gonzalez treatment, Issels whole body therapy, and Gerson therapy (see Gerson Therapy,).

Kelley's treatment includes dietary supplements (such as enzymes and large doses of vitamins, minerals, and amino acids), detoxification (such as fasting, exercising, and using laxatives and coffee enemas), a restricted diet, chiropractic adjustments, and prayer. Practitioners classify people into different metabolic types that form the basis for individual dietary and supplement recommendations.

The Gonzalez treatment is similar to Kelley's treatment and includes extracts or concentrates from animal organs such as thymus and liver (taken from beef or lamb) and digestive enzymes as part of the plan (see Cell Therapy).

Another form of metabolic therapy is Issels whole body therapy. Patients are asked to remove teeth that contain mercury dental fillings, follow a strict diet, and eliminate the use of tobacco, coffee, tea, and other substances that are considered harmful. Some patients are encouraged to undergo psychotherapy to relieve stress and deal with anger and emotional distress (see Psychotherapy).

Gerson therapy involves a strict dietary program, coffee enemas, and various mineral or chemical supplements.

What is the history behind it?

Gerson therapy was introduced by Max Gerson, MD, a German-born physician who immigrated to the United States in 1936. Gerson initially used the therapy for treating migraine headaches and tuberculosis and began using it for cancer in 1928. Kelley's treatment was developed in the 1960s by American orthodontist William Donald Kelley, DDS, MS. Nicholas Gonzalez, MD, became interested in metabolic therapy as a medical student in 1981 when he was asked to review Dr. Kelley's work.

In the 1970s and 1980s, Harold Manner, PhD, a biology professor, was also a major proponent of metabolic therapy. He claimed to have cured cancer in mice with injections of laetrile, enzymes, and vitamin A. In his version of metabolic cancer therapy, patients often received another unproven alternative substance, a chemical compound called dimethyl sulfoxide (see DMSO). In the early 1980s, Dr. Manner moved to Tijuana, Mexico, to treat patients (see Questionable Cancer Practices in Mexico). His clinic there is still open despite his death in 1988.

What is the evidence?

There is general agreement among scientists that there are differences in the metabolism of certain cells in people with cancer compared to people without cancer. There is also general agreement regarding the importance of attention to optimal nutrition as a component of conventional oncology care. Otherwise, there is no convincing clinical evidence that supports the claims made for metabolic therapy or any of its components. Some aspects of metabolic therapy may in fact be harmful.

An article on metabolic therapies on the Memorial Sloan-Kettering Cancer Center Web site concludes that "…retrospective reviews of the Gerson, Kelley, and Contreras metabolic therapies show no evidence of efficacy." And a review article in the Journal of Clinical Gastroenterology, "Colonic Irrigation and the Theory of Autointoxication," concludes that

    "[c]offee enemas are a hazardous derivative of colon therapy…. Its proponents claim that caffeine is absorbed in the colon and leads to a vasodilatation in the liver, which in turn enhances the process of elimination of toxins. None of this is proved, nor is there any evidence of the clinical efficacy of coffee enemas. Coffee enemas are associated with severe adverse reactions."

In a 1990 report from the Congressional Office of Technology Assessment, 3 oncologists reviewed the "best cases" collected by Dr. Gonzalez. In the vast majority of these cases, they found claims of benefit from metabolic therapy to be unconvincing. In addition, they found a few cases to be "unusual" at best, meaning that these patients lived longer than typical people with the same type and stage of cancer but concluded that this difference was probably due to statistical variation that occurs when "best cases" are selected from a large group of patients. A group of physicians who practiced alternative medicine (none of whom were cancer specialists) concluded that the alternative regimen was beneficial in some cases.

A small study of patients with pancreatic cancer -- conducted by Dr. Gonzalez and published in Nutrition and Cancer in 1999 -- found that patients treated with pancreatic enzymes survived longer than typical patients with pancreatic cancer. In a recent review of alternative cancer cures, an expert in integrative oncology research methods noted that, "The study was small and obviously prone to several biases. Not only is the comparison with national averages unadjusted for confounders (other factors that can affect outcome), but the principal results are based on patient selection; twelve patients who did not comply with treatment were excluded from analysis." A randomized clinical trial has been sponsored by the National Cancer Institute to evaluate the Gonzalez regimen for treating pancreatic cancer, but no results of this trial have yet been published in any available peer-reviewed medical journal.

Are there any possible problems or complications?

These substances may have not been thoroughly tested to find out how they interact with medicines, foods, or dietary supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Some aspects of metabolic therapy are considered dangerous. There are reports of complications related to liver cell injections, as well as nutritional deficiencies due to restricted diets. Several deaths have been directly linked to injecting live cells from animals (a practice called cell therapy). The drug laetrile may cause nausea, vomiting, headache, dizziness, and even cyanide poisoning, which can be fatal. Care should be taken to make sure that any diet containing raw meat or raw meat juice is free from contamination, given the increasing number of diseases that are known to be transmitted from animals to people.

Reports of illness and even deaths linked to colonic irrigation have been published in several medical journals. (See Colon Therapy for more information.) People with diverticulitis, ulcerative colitis, Crohn's disease, severe hemorrhoids, or rectal or colon tumors, or who are recovering from bowel surgery, may be at higher risk of bowel injury when using enemas. People with kidney or heart failure may be more likely to experience fluid overload or electrolyte imbalances. Enemas can also cause discomfort and cramps.

Women who are pregnant or breast-feeding should not use this method. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

Additional resources

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).

Dietary Supplements: What Is Safe?

The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

Complementary and Alternative Methods and Cancer

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer


Aetna InteliHealth. Colonic Irrigation. Accessed at: www.intelihealth.com/IH/ihtIH?d=dmtContent&c=358752&p=~br,IHW|~st,24479|~r,WSIHW000|~b,*| on June 10, 2008.

American Cancer Society. Unproven methods of cancer management. The metabolic therapy of Harold W. Manner, PhD. CA Cancer J Clin. 1986;36:185-189.

American Cancer Society. Questionable methods of cancer management: 'nutritional' therapies. CA Cancer J Clin. 1993;43:309-319.

Barrett S, Herbert V. Questionable cancer therapies. Accessed at: www.quackwatch.org/01QuackeryRelatedTopics/cancer.html on June 10, 2008.

Barrett S. Manner Metabolic Therapy. Accessed at: www.quackwatch.org/01QuackeryRelatedTopics/Cancer/manner.html on June 10, 2008.

Centers for Disease Control and Prevention. Amebiasis associated with colonic irrigation: Colorado. MMWR Morb Mortal Wkly Rep. 1981;30:101-102.

Eisele JW, Reay DT. Deaths related to coffee enemas. JAMA. 1980;244:1608-1609.

Ernst E. Colonic irrigation and the theory of autointoxication: A triumph of ignorance over science. J Clin Gastro. 1997;24:196-198.

Eyre HJ, Lange DP, Morris LB. Informed Decisions: The Complete Book of Cancer Diagnosis, Treatment, and Recovery, 2nd ed. 2002; Atlanta: American Cancer Society.

Gonzalez NJ, Isaacs LL. Evaluation of pancreatic proteolytic enzyme treatment of adenocarcinoma of the pancreas, with nutrition and detoxification support. Nutr Cancer. 1999;33:117-124.

Green S. Nicolas Gonzalez treatment for cancer: gland extracts, coffee enemas, vitamin megadoses, and diets. Accessed at: www.quackwatch.org/01QuackeryRelatedTopics/Cancer/kg.html on June 10, 2008.

Green S. A critique of the rationale for cancer treatment with coffee enemas and diet. JAMA. 1992;268:3224-3227

Istre GR, Kreiss K, Hopkins RS, et al. An outbreak of amebiasis spread by colonic irrigation at a chiropractic clinic. N Engl J Med. 1982;307:339-342.

Memorial Sloan-Kettering Cancer Center. Metabolic therapies. Accessed at: www.mskcc.org/mskcc/html/69299.cfm on June 10, 2008.

National Cancer Institute. Gemcitabine compared with pancreatic enzyme therapy plus specialized diet (Gonzalez Regimen) in treating patients who have stage II, stage III, or stage IV pancreatic cancer. Accessed at: http://clinicaltrials.gov/ct/show/NCT00003851?order=1 on June 10, 2008.

US Congress, Office of Technology Assessment. Unconventional Cancer Treatments. Washington, DC: US Government Printing Office; 1990. Publication OTA-H-405.

Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 11/01/2008
Last Revised: 03/08/2012