Supplements and Herbs

Dr Manner: laetrile, enzymes and vitamins as a cancer treatment

Animal experiments show dramatic tumor regressions

Copyright © 2019 Healing Cancer Naturally

Dr Harold W. Manner received both his Master of Science and Ph.D. from Northwestern University. He was the Chairman of the Biology Departments of Syracuse University, St Louis University and Loyola University of Chicago. He published over 50 scientific articles and six college level textbooks.

After 30 years of academic teaching and research, including as Professor at the St Louis University and Loyola University, he retired in 1982 to devote his full time to metabolic therapy. He established and headed a foundation in Mexico providing treatment for cancer based on his metabolic therapy.

He had noted discrepancies in previous published reports about the toxicity of laetrile in mice. In his book, The Death of Cancer, he describes various experiments he conducted.

In the first test he used 40 experimental mice divided into 4 groups of 10 together with a further control group of 10 and administered laetrile in different amounts.

At the end of the 15 day test period no deaths had occurred. In fact the eyes remained bright and the hair coat shiny in all groups at the end of the test. "The results indicate that daily doses of 2,000 mg/kg/day can be used by investigators in tumour regression in mice without danger of toxicity or lethality."

He noted there had been suggestions that any administration of laetrile other than by mouth was non-toxic because it passed out of the body in the urine untouched. Therefore laetrile was of no value.

The second test used 350 mice divided into 7 groups of 50 each. The results were that the experimental animals showed traces of thiocyanate and hippuric acid in the urine proportional to the laetrile with which they had been injected while the control animals did not.

Therefore, laetrile injected rather than taken orally is broken down in the body and does not pass through untouched. The body is able to neutralize the cyanide and benzaldehyde given off.

The third test was related to the distribution of beta-glucosidase and rhodanese in cells. He compared the liver, brain and muscle tissues in normal versus malignant animals as well as testing the tumour itself. He found the cancer cells to be much lower in rhodanese than the normal cells tested as well as being much higher in beta-glucosidase.

These results tend to support Ernst Krebs' theory of why laetrile works against cancer cells in that the beta-glucosidase acts as an unlocking mechanism for the cyanide and benzaldehyde locked up within laetrile while the rhodanese in healthy cells renders those elements harmless.

Dr Manner reviewed other previous tests that had appeared to show that laetrile does not work, in particular repeated tests at the Memorial Sloan-Kettering Institute in New York City and the National Cancer Institute in Washington D.C.

They had found that tumours did not stop growing nor did they regress but continued growing at an alarming rate and animals died at the same time as the control animals. In other words they appeared to come to the same conclusion, namely that laetrile had no effect on tumours.

On reviewing those experiments he found two fundamental mistakes. Firstly, those and Dr Manner’s own initial experiments had been using what is commonly called a transplanted tumour.

Mice are obtained which are already afflicted with a tumour, often an axial sarcoma, meaning a cancer of the connective tissue rather than one restricted to an organ. These tumours are then excised (removed) from the animal’s body and homogenized (ground up) in saline solution. The grinding process dislodges individual cells which are drawn up in a syringe.

Approximately one million of these actively reproducing cancer cells are then injected into healthy animals. The rapidly dividing cells soon form their own tumour mass which grows at an alarming rate in the same way as if the solution had been injected into a glass dish containing a culture medium.

The benefit for a researcher is a cheap and easy to obtain supply of infected mice. However no human acquires cancer in this way, instead it develops over time after something has gone wrong in the body.

Therefore he located a laboratory with a strain of mice bred in such a way that they had an inherent weakness for the development of breast cancer in the later stages of their lives. This procedure was more expensive and took more time however it meant that an animal’s condition more closely resembled the way a human contracts cancer.

Secondly, after reviewing laetrile clinics around the world it became clear that laetrile was never used by itself but always in conjunction with a complete therapeutic programme. The common elements were laetrile, large doses of enzymes, usually pancreatic enzymes[1], and the use of vitamin preparations, particularly vitamins A and C.[2]

The next experiment used 84 experimental animals injected with differing combinations of three substances. Firstly, they injected amygdalin intramuscularly in the rump area.

Secondly they administered 333,333 International Units of emulsified vitamin A orally. The vitamin was emulsified to be absorbed by the lymphatic system rather than the circulatory system, thereby bypassing the liver and eliminating the possibility of vitamin A liver toxicity. To emulsify means to convert into a liquid in which particles are evenly distributed.

Thirdly they injected enzymes into and around the tumour every second day. The preparation contained enzymes from the pea, the lentil, the papaya plant, and from calf thymus and bovine pancreas.

In 4 to 6 weeks the tumours were completely gone on 75 (90%) of the 84 experimental animals. The tumours on the other 9 (10%) were in various stages of regression at the close of the experiment.

"Although we admit to ignorance at this time regarding the mechanism of action of laetrile therapy we do know one thing for certain–IT WORKS".

The experiments were published in scientific journals and are set out in his below-listed book, The Death of Cancer.

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The Death of CancerThe Death of Cancer [Amazon partner link — commissions earned]

by Harold Manners, MD, PhD

Laetrile Case Histories; The Richardson Cancer Clinic Experience (2005) [Amazon partner link — commissions earned]

by John A. Richardson MD and Patricia Griffin

Read sample cancer survivor stories from the book.


1 Pancreatic (proteolytic) enzymes are a cancer treatment in their own right, see Transitional Cell Carcinoma of the Bladder Healed Part 2: The Use of Proteolytic (Pancreatic) Enzyme Treatment.

2 See for instance Dr Binzel's treatment: vitamin B 17 plus diet.

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