National Cancer Institute

Expert-reviewed information summary about the Gonzalez regimen as a treatment for people with cancer. Note: The information in this summary is no longer being updated and is provided for reference purposes only.

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the use of Gonzalez Regimen in the treatment of people with cancer. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.

This summary is reviewed regularly and updated as necessary by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).

Gonzalez Regimen


NOTE: The information in this summary is no longer being updated and is provided for reference purposes only.

This cancer information summary provides an overview of the Gonzalez regimen as a treatment for people with cancer. The summary includes a brief history of the science and philosophies of care that have influenced development of the regimen, the results of research and clinical studies, and side effects that have been associated with this treatment approach.

This summary contains the following key information:

  • The Gonzalez regimen is a complex cancer treatment that is tailored by the practitioner for each specific patient.
  • Existing clinical data concerning the effectiveness of the Gonzalez regimen as a treatment for cancer are limited with conflicting results.
  • Pancreatic enzymes taken orally are the primary agents within the regimen thought to have direct antitumor effects. The enzymes are derived from porcine (pig) sources.
  • The regimen also includes specific diets, vitamin and mineral supplements, extracts of animal organs, and coffee enemas.
  • The Gonzalez regimen is currently available only to the patients in one clinical practice.
  • A variety of diet regimens similar to those in the Gonzalez regimen are associated with cancer prevention, but none have been shown to be effective as cancer treatments.
  • Compliance with the Gonzalez regimen may be extremely difficult for patients because of the large number of pills taken per day (150) and the strict dietary protocols.

Many of the medical and scientific terms used in this summary are hypertext linked (at first use in each section) to the NCI Dictionary of Cancer Terms, which is oriented toward nonexperts. When a linked term is clicked, a definition will appear in a separate window.

Reference citations in some PDQ cancer information summaries may include links to external websites that are operated by individuals or organizations for the purpose of marketing or advocating the use of specific treatments or products. These reference citations are included for informational purposes only. Their inclusion should not be viewed as an endorsement of the content of the websites, or of any treatment or product, by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board or the National Cancer Institute.

General Information

The Gonzalez regimen combines prescribed diets, nutritional supplements, coffee enemas, and pancreatic enzymes in a cancer management program. The regimen is intended to detoxify the body, correct nervous system imbalances that might lead to impaired general health, and support natural immune processes. The pancreatic enzymes are thought to be the specific anticancer component of the Gonzalez program.

Two major concepts underlie use of the Gonzalez regimen in cancer treatment. The first concept is that the pancreas, like the liver, is an organ that performs a detoxification function and that pancreatic enzymes help the body eliminate toxins and help normal cells repair damaged cells. The second concept is that cancer and most other human illness are related to physiological imbalances created by environmental toxins either consumed in food or contacted in the environment.

Proponents of the Gonzalez regimen believe that toxins from sources such as processed foods and environmental pollution are responsible for human cancers. These toxins are thought to accumulate in tissues and over time create imbalances in the autonomic nervous system, diminish the normal immune response, and give rise to cellular damage that can lead to cancer. If these toxins could be neutralized and eliminated from the body, proponents believe, both early and established cancers would be halted, and general health would be restored.

According to the developer of the Gonzalez regimen, the diets used in this regimen are chosen for each patient according to individual metabolic profiles established at the time of initial evaluation through various tests, including hair analysis. There are ten basic diets and 90 variations. The diets emphasize organic foods. Each diet carries a particular focus and can range from strictly vegetarian diets to diets high in meat and fat. Variations in the diets correlate with the theory that imbalances in the autonomic nervous system are exacerbated by a diet that is inappropriate for the patient’s metabolic type.

Nutritional supplements employed in the Gonzalez regimen include vitamins, minerals, trace elements, amino acids, and extracts of animal organs (e.g., thymus and liver extracts from sheep or cows). As with the dietary protocols, the nutritional supplements are intended to correct autonomic nervous system imbalances.

The major feature of the Gonzalez regimen is freeze-dried porcine pancreatic enzyme (PPE) administered in capsule form as part of the nutritional supplementation aspect of the program. Obtained from pigs, PPE is considered to be the primary cancer-fighting component in the regimen and to contribute to the overall detoxification process.

Proponents of the regimen believe that the pancreatic enzymes are delivered to the bloodstream and help the body eliminate and destroy abnormal cells, waste material, and abnormal proteins that are toxic to the body. As the body detoxifies, the cancerous tumors tend to shrink.

Coffee enemas are also included as part of the detoxification process. The enemas are administered twice daily. The use of coffee enemas is based on a belief that coffee introduced into the lower intestinal tract will improve liver function and stimulate emptying of the gallbladder, thereby enhancing the elimination of toxins and waste products from the body.

The Gonzalez regimen is available only to private patients of its New York-based practitioner.

Pancreatic enzymes are sold in the United States as either prescription drugs indicated for pancreatic insufficiency or over-the-counter (OTC) dietary supplements. As of 2004, those sold as prescription drugs must have a New Drug Approval from the US Food and Drug Administration (FDA) to be marketed legally in the United States. Pancreatic enzymes sold as OTC dietary supplements are regulated as foods, not drugs. Dietary supplements in the United States are therefore sold without a requirement of a market approval by the FDA, as long as they do not claim to treat or prevent a specific disease or condition. According to the developer of the Gonzalez regimen, most OTC preparations or other commercially available pancreatic enzymes are not effective against cancer.

For the FDA, PPE falls under the category of a new prescription drug that is under investigation. To conduct clinical drug research in the United States, researchers must file an Investigational New Drug (IND) application with the FDA. To date, only one group of investigators is known to have IND approval to study this pancreatic enzyme preparation as a treatment for cancer. The IND process is confidential, and the existence of an IND can be disclosed only by the applicant(s).


The Gonzalez regimen was developed by Dr. Nicholas Gonzalez, who became interested in the use of pancreatic enzymes and dietary protocols as a possible treatment for cancer as a second-year medical student when he learned of a cancer treatment approach developed by a Texas dentist, William Donald Kelley, D.D.S. Dr. Kelley’s approach espoused, among other things, the use of pancreatic enzymes administered orally as anticancer agents. The use of enzymes as a treatment for cancer was originally proposed nearly a century ago and then resurfaced in the work of Dr. Max Gerson in the 1940s. The Gonzalez regimen was developed from these earlier theories and approaches.

A key concept underlying the original use of pancreatic enzymes for cancer treatment is the trophoblastic theory of cancer. When a human egg is fertilized by sperm, the early celldivisions produce a small ball of cells, which give rise to the blastocyst (preimplantation embryo). The blastocyst possesses a surrounding layer of cells known as the trophectoderm, which is made of individual cells called trophoblasts. Responsible for protecting the developing blastocyst and for mediating its attachment to the wall of the uterus, trophoblasts create the placenta. During the process of attaching the blastocyst to the uterine wall, trophoblasts express invasive qualities similar to those found in cancer cells. Trophoblasts, however, cease their invasive activity once the placenta is in place and functioning and then differentiate into other cell types.

When Scottish embryologist Dr. John Beard first observed the invasive activity of trophoblasts in 1902, he speculated on the similarities between these cells and cancer cells. In addition, he observed that trophoblast invasiveness begins to decline at about the same time that the pancreas in the developing fetus begins to function. He also theorized that maternal pancreatic enzymes might play a role in containing trophoblastic invasiveness in the uterus. These considerations led to his proposal that cancer cells, like trophoblasts, arise from primordial germ cells. Dr. Beard also thought that some of these primordial cells—carrying latent capacities for invading tissues—could escape and spread throughout the body of the developing fetus. He thought it was possible that pancreatic enzymes modulated the degree of trophoblastic invasiveness in the uterus, he suggested that these same enzymes play a role in either limiting or eliminating cancerous cells elsewhere in the body. Dr. Beard worked before the advent of molecular biology and human genetics. Although unable to experimentally establish that pancreatic enzymes had anticancer effects, he published papers and a book about his theory between 1902 and 1911. Other scientists of the time raised significant objections to the trophoblastic theory of cancer, and it was never broadly accepted.

As Dr. Beard had before him, Dr. Kelley also asserted that trophoblasts and cancer cells have a common origin in primordial germ cells. Dr. Kelley maintained, furthermore, that cancer was initiated when primordial germ cells migrated to a point in the body already weakened by toxic exposure and nervous system imbalance. At these presumably compromised sites, the germ cells met no opposition from the immune system and initiated an aggressive invasion of normal tissue, creating malignancy. Dr. Kelley’s treatment approach was based on the belief that primordial germ cells are the single cause of all cancers, no matter where they occur, and that pancreatic enzymes are able to suppress or destroy cancers.

Dr. Gonzalez incorporated many of Dr. Beard’s and Dr. Kelley’s key points into his own treatment regimen. In addition, the Gonzalez regimen includes the rigorous dietary protocols, nutritional supplements, and coffee enemas that can be found in the earlier work of Dr. Max Gerson. The Gonzalez regimen now includes use of pancreatic enzymes, along with nutritional supplements, coffee enemas, and prescriptive diets based on a theory of autonomic dominance.

An example of the Gonzalez regimen for a patient with pancreatic adenocarcinoma would be the following:

The total number of capsules taken per day by each cancer patient on the Gonzalez regimen typically ranges from 130 to 160, taken with and away from meals. In addition, the Gonzalez regimen uses coffee enemas on the premise that coffee absorbed through the intestinal wall will improve liver and gallbladder function and help increase the removal of toxic waste from tumor breakdown. At this time there is no scientific evidence that coffee enemas have any specific effects on increased liver function, effects on tumor breakdown detoxification, or a role in the treatment of any cancer.

Doubts exist about the effectiveness of oral administration of pancreatic enzymes because pancreatic enzymes were not thought to be transported intact from the gut to the bloodstream. Evidence now suggests that intact digestive enzymes can be absorbed and resecreted by the pancreas, in a manner similar to the liver recycling of bile salts and hormones.

Laboratory/Animal/Preclinical Studies

Directly relevant laboratory or animal data concerning the anticancer potential of the Gonzalez regimen are limited. Published animal studies focus on the role of pancreatic enzymes in cancer treatment rather than the regimen as a whole.

An animal study published in 1999 measured the ability of orally administered porcine pancreas preparation (PPP) to slow or halt the growth of cancer and to inhibit metastasis. Sixty Fischer F344 female rats were divided into five groups of 12 each. All groups were fed the same basic diet. After 5 days, R13762 transplantable rat mammary tumor was implanted into a mammary fat pad on each rat. The animals were maintained on their assigned diets for another 40 days. After the tumors had taken hold, two groups were given a high dose of PPP (20% by weight) and two groups were given a lower dose (2% by weight). The fifth group was used as a control and received no enzymes. In addition, one group from each of the PPP-dosed rat groups was also given a magnesium citrate supplement because magnesium is often given with PPP in clinical practice.

Results showed that PPP had no effect on tumor growth, and PPP alone did not show any significant effect on the amount of metastases. However, when the rate of metastases in the rats dosed at the 20% rate was compared with those dosed at 2%, it was noted that there was an increase in metastases in the rats given a higher dose of PPP. The lowest rate of metastases was seen in the rats given the 2% dose plus magnesium citrate.

In another study, the effects of porcine pancreatic enzyme (PPE) extracts on survival and tumor growth were examined in 5- to 6-week-old male beige X-linked immunodeficient mice. In the survival study, two groups of mice received pancreatic cancer cells AsPc1 injected into their pancreas. The treatment group (14 mice) received PPE in water at a dose of 400 mg/kg of body weight, which corresponds to the dose used in patients receiving the Gonzalez regimen. The control group (13 mice) was given only water. After death, the pancreas was removed and measured for volume and weight. The median survival rates for the treatment group and the control group were 43.5 days and 35 days, respectively. At day 35, the survival rates were 79% in the treatment group and 38% in the control group. In addition, the control mice showed reduced activity as compared with the treatment group, which showed normal activity and no signs of disease. In general, the size of tumors and the rate of invasion in the liver and peritoneum correlated with length of survival time.

In the tumor growth segment of this study, a second group of 30 mice was taken through the same procedures. Tumor size and weight were measured in two mice from each group on day 52, and again in two mice from the control group and five mice from the treatment group on day 60. Ascites were much more apparent in the control group than in the treatment group. Physical activity among the treated mice was much greater than in the control group. Results showed that the treatment group had significantly smaller tumors than the control group in both weight and volume. The mean tumor weight was 1.2 g in the control group and 0.75 g in the treatment group. The tumor volume was 0.42 cm in the treatment group and 0.91 cm in the control group. All mice in the control group showed steatorrhea, hyperglycosuria, hyperbilirubinuria, and ketonuria in the early stages of tumor growth, whereas in the treated group only a few mice showed these abnormalities in the final stages. There were no differences in the tumors of the treatment and control groups in the expression of growth factors, epidermal growth factor receptor, or apoptotic rate.

Human/Clinical Studies

The anticancer efficacy of the Gonzalez regimen has been investigated in two human studies (CPMC-IRB-8544 ), both involving patients with pancreatic cancer.

The first study, a prospective nonconsecutive case series conducted by the developer and an associate, included 11 patients diagnosed with adenocarcinoma of the pancreas (stage II through stage IV). None of the patients had received chemotherapy or radiation therapy, and none had undergone surgical resection with curative intent. All the patients had pancreatic tumors that were either unresected or partially resected. Survival from the time of diagnosis was the only study endpoint, and all 11 patients (including one who left the study) were included in this survival analysis.

The investigators reported a median survival time of 17 months and a mean survival time of 25.2 months for these patients. Nine patients (82%) survived 1 year, five patients (45%) survived 2 years, and four patients (36%) survived 3 years. At the time the study was reported, two patients were alive: one who had survived 3 years, and one had survived 4 years. The researchers concluded that the 1-year and 2-year survival percentages for this group of patients were superior to those observed for other U.S. patients diagnosed with adenocarcinoma of the pancreas (1-year survival, all stages = 25%; 2-year survival, all stages = 10%).

The small number of patients in this study and the absence of a control group are limitations that raise doubts about the reliability of its findings. It is possible that important, unidentified differences between these patients and other patients diagnosed with stage II to stage IV pancreatic cancer contributed to the relatively long survival. The investigators report that 25 additional patients with pancreatic cancer were seen during the study period but were excluded from study participation. Eleven of these patients were excluded on the basis of comorbidities, previous treatment, or delay between diagnosis and beginning the program; 14 otherwise eligible patients were excluded on the grounds that they chose not to start the program, complied only briefly, or predicted noncompliance.

The second study is a nonrandomized prospective case-control observational study sponsored by the National Center for Complementary and Integrative Health and the National Cancer Institute in which median survival and quality of life were found to be better in patients treated with gemcitabine-based (i.e., other drugs may be included) chemotherapy than for patients treated with the Gonzalez regimen. This study was originally planned for randomization but changed after few patients elected to participate in the randomized trial. The same eligibility criteria were used to select patients for both treatment arms. The results of this study were reported in the peer-reviewed Journal of Clinical Oncology. According to the report, 70 patients were evaluated for the study and 55 were enrolled: 23 in the gemcitabine arm and 32 in the enzyme treatment arm. The enzyme treatment included orally ingested proteolytic enzymes, nutritional supplements, detoxification, and an organic diet (as used in the pilot study by Gonzalez and Isaacs). Patients received three pancreatic enzyme capsules and two magnesium citrate capsules with each meal. The patients also took specified numbers of capsules with magnesium citrate and Papaya Plus every 4 hours on an empty stomach. The dose for patients with stage II disease was 69 enzyme capsules per day, and the dose for patients with stages III or stage IV was 81 capsules per day. After day 16, patients had a 5-day rest period and then resumed treatment on day 22. Patients in the experimental arm received proteolytic treatment under the care of a practitioner familiar with the regimen; those in the chemotherapy arm received treatment by the oncologist they selected. Treatment could be adjusted by the physician, and it could be increased for cancerprogression. The gemcitabine treatment patients received various gemcitabine-containing regimens, with 19 of the 23 patients receiving a combination of gemcitabine, capecitabine, and docetaxel. The two groups had similar clinical characteristics. The median survival for the patients in the gemcitabine arm was 14 months and, on the enzyme arm, 4.3 months. The quality of life as measured by the FACT-PA was also better in the chemotherapy arm. The paper does not list Dr. Gonzalez as an author, and does not identify him as participating in the study; however, Dr. Gonzalez published comments on his website indicating his participation in the study and detailing his concerns about how the study was conducted, including patient compliance with the prescribed treatment in the enzyme arm.

No data concerning the effectiveness of the Gonzalez regimen for the treatment of cancer patients with other types of cancer have been reported, despite claims that a variety of cancers can be treated. In addition, there is no safety or efficacy information on the regimen in children. No clinical trials of this regimen have been conducted in children, and this extremely difficult regimen may be prohibitive in young children.

Adverse Effects

The developer of the Gonzalez regimen has reported the following adverse effects associated with the regimen: intestinal gas; occasional bloating and indigestion, apparently related to ingestion of porcine pancreatic enzyme; and flu-like syndromes, allegedly associated with detoxification, including low-grade fever, nonspecific myalgia (muscle aches), and nonspecific skin rashes. The cases found in the literature on coffee enema are not adequate to support an adverse effect from coffee enemas alone. There are rare reports of adverse events unrelated to the coffee enemas in patients receiving them. It should be remembered that clinically significant changes in blood chemistries can occur with excessive use of enemas of any kind.

Summary of the Evidence for the Gonzalez Regimen

Existing clinical data concerning the effectiveness of the Gonzalez regimen as a treatment for cancer are limited and inconclusive. One clinical study, a nonconsecutive case series involving 11 patients with pancreatic cancer, has been reported. Another clinical study involving 55 patients with pancreatic cancer was published in the peer-reviewed Journal of Clinical Oncology in August 2009. No data concerning the effectiveness of the Gonzalez regimen in patients with other types of cancer have been reported.

To assist readers in evaluating the results of human studies of integrative, alternative, and complementary therapies for cancer, the strength of the evidence (i.e., the levels of evidence) associated with each type of treatment is provided whenever possible. To qualify for a level of evidence analysis, a study must:

  • Be published in a peer-reviewed scientific journal.
  • Report on a therapeutic outcome or outcomes, such as tumor response, improvement in survival, or measured improvement in quality of life.
  • Describe clinical findings in sufficient detail that a meaningful evaluation can be made.

Separate levels of evidence scores are assigned to qualifying human studies on the basis of statistical strength of the study design and scientific strength of the treatment outcomes (i.e., endpoints) measured. The resulting two scores are then combined to produce an overall score. For an explanation of the scores and additional information about levels of evidence analysis of CAM treatments for cancer, refer to Levels of Evidence for Human Studies of Integrative, Alternative, and Complementary Therapies.

Changes to This Summary (04/11/2016)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Editorial changes were made to this summary.

This summary is written and maintained by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, which is editorially independent of NCI. The summary reflects an independent review of the literature and does not represent a policy statement of NCI or NIH. More information about summary policies and the role of the PDQ Editorial Boards in maintaining the PDQ summaries can be found on the About This PDQ Summary and PDQ® - NCI's Comprehensive Cancer Database pages.

About This PDQ Summary

Purpose of This Summary

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the use of Gonzalez Regimen in the treatment of people with cancer. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.

Reviewers and Updates

This summary is reviewed regularly and updated as necessary by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).

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Levels of Evidence

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National Cancer Institute: PDQ® Gonzalez Regimen. Bethesda, MD: National Cancer Institute. Date last modified . Available at: Accessed .

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