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Yeast and Chronic Fatigue

by Bruce Semon, M.D., Ph.D.

This page is based on Dr. Bruce Semon’s clinical experience and research. This page discusses how yeast can cause Chronic Fatigue Syndrome. For detailed explanations, including an more case studies, and how you can treat Chronic Fatigue–we recommend that you read An Extraordinary Power to Heal.

Dr. Semon is available to see patients and for consultation. For more information about his medical practice, call 1-877-332-7899, or click here.


The following is a description of a woman with chronic fatigue whose symptoms were treated by safe effective therapy of a change of food choices (found in our books An Extraordinary Power to Heal (2003) and Feast Without Yeast (1999)) and the non-absorbed anti-yeast medicine nystatin. This case is taken from Dr. Semon’s book, An Extraordinary Power to Heal (2003). After the case, we present an explanation of why this treatment works.

Case of twenty years of chronic fatigue treated with anti-yeast therapy

Edna, 48, was bothered by fatigue. She needed one to two naps per day and was sleeping ten to twelve hours per night. The rest of the time she felt sick, as if she would get a cold. She was also nauseated. She was disabled and was receiving social security benfits. She had quit work eight years previously at a college level job. Now she only worked very part-time. She had experienced fatigue for twenty years.

She had low grade fevers regularly for three years. She used to have sore throats and headaches, then fevers, all with fatigue. She felt the worst in the afternoon. Her fevers were usually in the afternoon.

She had seen another doctor, a few months previously, who had prescribed Diflucan (an anti-fungal drug), Valtrex (an anti-viral drug), and gamma globulin injections (gamma globulin is the fraction of the blood which had antibodies for fighting some kinds of infections). She thought that these therapies had perhaps helped a little but she did not want to continue them.

She also had diarrhea and was labeled as having colitis. She had colonoscopy in the past.

She stated she ate a good diet. She had started part of the anti-yeast diet already, excluding vinegar and malt about six weeks previously and she said she felt a little better. But she said many things had helped temporarily and she was afraid that these dietary changes would stop helping.

She was depressed over being sick. She had felt a little better in the last few weeks but the diarrhea was intermittent. She had a history of abdominal pain although she said she was not bothered by this now.

She had mononucleosis fourteen years previously, which had lasted a long time. She had an 18 year old son and she had taken antibiotics as a child.

Edna had a college degree.

I recommended she stay with the anti-yeast diet (and make sure she was doing all the diet) and that she start nystatin.

She came back five weeks later and stated that she was feeling better. Her fevers were now only occasional instead of daily. She no longer needed to take naps. She was sleeping through the night for 8-9 hours. She no longer needed one to two naps per day. The sick feelings were all gone. Things did not bother her as much and she could handle stress better. She had much more energy.

Her diarrhea was gone. Her bowel movements were normal. Her mood was much improved. She no longer had abdominal cramping.

She stated she could now go back to work.

Twenty years of fatigue was over in less than eleven weeks.


Explanation of why anti-yeast therapy treats Chronic Fatigue

What follows is an abbreviated explanation of why anti-yeast therapy works to help sufferers of Chronic Fatigue Syndrome. I give a much more detailed explanation in our book, An Extraordinary Power to Heal (2003).

Chronic fatigue syndrome is a disabling condition which robs its sufferers of their energy to function in life. In the academic world of medicine, there is no known cause and no treatment. I have helped many sufferers of chronic fatigue syndrome by treating the yeast Candida albicans. Let me explain why this treatment is helpful.


The yeast Candida albicans is a normal resident inside of our intestinal tract. This yeast can also be found at times in the mouth. Sometimes this yeast overgrows and the doctor recognizes this overgrowth of yeast as a yeast infection in the mouth called thrush.

Bacteria are also resident inside the intestinal tract, sharing space with the yeast. When a person uses antibiotics, for example to treat strep throat, the antibiotics kill the bacteria. This leaves space for the yeast. The yeast then grow to fill in the spaces. Even after the antibiotics have been stopped, the yeast continue to grow at a higher level. Pregnancy and the use of birth control pills can also make yeast grow more. The overgrowth of yeast can cause problems in some people.

Yeast make a number of chemical compounds which are then picked up and absorbed into the body. These compounds are quite toxic (poisonous) to the nervous system. These compounds include toxic alcohols and aldehydes, as well as the powerful nervous system poison hydrogen sulfide.

Alcohols depress the nervous system and at least some aldehydes are anesthetic agents, which of course put the brain to sleep. These chemicals slow the brain down so that the brain no longer works correctly. These chemicals should be cleared by the liver so that these chemicals never reach the brain. However in some people, these chemicals are apparently not cleared, reach the brain, and cause symptoms.

In addition to yeast that lives in your body, you can also take in chemicals through your food. These chemicals also slow down the brain. Barley malt, the raw material for making beer, contains chemicals which slow down the brain. Vinegar also contains such chemicals. Such chemicals can also cause problems with fatigue. I explain exactly which foods cause the problems, and how to eliminate them while still eating great food, in An Extraordinary Power to Heal(2003). and Feast Without Yeast:4 Stages to Better Health. .

Literally, these chemicals cause the brain and body not to be able to function at their normal level of energy. When you remove these chemicals, both by treating the intestinal yeast and by changing the diet to exclude chemicals which slow the brain down, the body’s energy returns.

The way to reverse this intestinal yeast problem is to take the anti-yeast drug nystatin. This drug is not absorbed and kills the yeast living in the intestinal tract. Then the yeast can no longer make the toxic chemical compounds.

Second, the diet contains many foods which contain yeast compounds. Some of these yeast chemicals are toxic to bacteria and will clear space for the yeast to grow again. If these yeast chemicals are left in the diet, nystatin will not do much good because the yeast keeps growing back. So, to treat yeast, these foods must be removed from the diet. Taking away these dietary yeast products enables the body to clear itself of yeast chemicals.

Fortunately, because nystatin is not absorbed, nystatin causes no side effects except for a little nausea. No side effects are reported in Physicians Desk Reference. To my knowledge, no harmful side effects have ever been caused by the use of nystatin. This is a very low-risk therapy.

The diet for Candida problems consists of removing fermented foods from the diet. The worst offenders are alcoholic beverages and non-alcoholic beer, vinegar, barley malt, chocolate, pickles, and aged cheese. Most people feel better just by eliminating these foods, which I call Stage I of the 4 stage diet. An Extraordinary Power to Heal (2003) gives you detailed instructions, day by day and week by week, about how to eliminate toxic foods from your diets. We give you the recipes and menus to do this in Extraordinary Foods for the Everyday Kitchen (2003) and Feast Without Yeast(1999).

All the fatigued patients I have seen who have changed their diets and taken nystatin have improved. The level of improvement depends on the patient. Even people who have been fatigued for years or had not even been able to get out of bed improve.

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