Juices must be freshly squeezed every hour so that the oxidizing enzymes will not be destroyed by light or air. Even the type of juice extractor and grinder are specially selected. Standard home juicers are not recommended because the electric charge produced by their centrifugal actions destroys enzymes and their preparation process mixes oxygen into the juices, hastening their decomposition. Gerson patients are encouraged to buy a more expensive, stainless-steel grinder and press.

After treatment at the Gerson hospital, patients are advised to continue the regimen at home for one and a half years or more, until the liver, pancreas, and oxidation, immune, and other systems have been restored sufficiently to prevent a recurrence of cancer. The support of family and close friends-both emotionally and on a practical level-is believed to play a vital role in the therapy's success.

For those who do persevere, the benefits can be dramatic. "It's a lot of work," says Charlotte Gerson, "but those people who want to be well, and remain well, with their bodies rebuilt, with their organs rebuilt, and normal and functioning, they go through it, and they do the job, and they regain health in all areas, whether we are talking about cancer, multiple sclerosis, rheumatoid arthritis, glaucoma, kidney disease, or even diabetes."

The therapy is multifaceted. Dr. Gerson placed great emphasis on the liver, which he believed to be the body's most important organ in defeating malignancy. He maintained that nearly all cancers were allowed to develop because of poor liver function. Support for this view comes from Dr. Jesse Greenstein, former chief of the National Cancer Institute's biochemistry laboratory. In his 1954 book, Biochemistry of Cancer, Greenstein wrote, "There seems to be little doubt that hepatic insufficiency is a concomitant phenomenon with cancer." According to Dr. Raymond Brown, former investigator at Sloan-Kettering Institute for Cancer Research, Gerson's "thesis that a damaged liver is a primary precursor of degenerative disease is consistent with current concepts that liver status reflects the functional capacity of the reticuloendothelial system.", The reticuloendothelial system defends against infection and disposes of the products of cell breakdown. It is composed of macrophages, liver cells, and cells of the lungs, bone marrow, spleen, and lymph nodes.

The liver, the body's largest organ, weighs seven to ten pounds and performs a multitude of tasks. Among its vital functions are metabolizing essential fats (and thus preventing their accumulation in the bloodstream), synthesizing necessary blood proteins, breaking down and eliminating toxic substances, and secreting bile, which is stored in the gallbladder and the enlarged bile duct. Bile, which empties into the small intestine, acts as a carrier for all liver wastes. One reason animal proteins are drastically reduced on the Gerson diet is that they have been found to interfere with liver-boosting medications and to impede the detoxification process. Keeping animal protein at a minimum frees the protein-dissolving enzymes to "digest" cancer tissue rather than food, according to Max Gerson.

Gerson also found that both animal and vegetable fats have the effect of promoting tumor growth. Whenever he eliminated fats from his cancer patients' diets, the results improved substantially. Recent research supports his finding. Studies show that the higher the level of cholesterol and fats in the blood of cancer patients, the less chance the patients have of surviving. Cancer patients receiving Gerson therapy therefore avoid both animal and vegetable fats. An exception is linseed oil, which helps the body transport vitamin A. Linseed oil has been shown to have antitumor action, and it is rich in an essential fatty acid that reduces blood viscosity. Low blood viscosity correlates with a decreased tendency to spreading (metastases) of cancer.