Smelly Gas a Clue to CFS Testing and Therapy

Published: August 7, 2012

Bowel symptoms are a routine part of chronic fatigue syndrome, fibromyalgia and ME (myalgic encephalomyelitis). These are caused by many problems including numerous bowel infections and autonomic nervous system dysfunction. The autonomic nervous system is what controls contractions that move food in the proper direction going from your stomach toward the colon and anus.

Bowel infections and autonomic dysfunction results in acid reflux, nausea, diarrhea, gas, bloating and constipation — and most people with CFS/FMS have some or all of these symptoms. In our experience, these generally resolve when addressing the issues with the SHINE Protocol. Eliminating candida/yeast overgrowth is especially helpful (I recommend candida be addressed in almost everyone with CFS or fibromyalgia), as is addressing any parasitic infections which in our study were present in 1/6 of CFS patients. Small intestinal bacterial overgrowth (SIBO) is also common in CFS/FMS and is actually aggravated by an underactive thyroid.

So What's New? I Know I Have Bowel Infections

What's new is the hypothesis that hydrogen sulfide (which causes a rotten egg smell and is the major reason why intestinal gas sometimes smells awful) is also being produced at toxic levels by certain unhealthy bacteria — and aggravating CFS/ME symptoms. It is also hypothesized that the presence of toxic metals (e.g., mercury, nickel, etc.) can make the hydrogen sulfide even more toxic and block energy production in people's mitochondrial energy furnaces.

Along with this hypothesis, a home test kit to measure for hydrogen sulfide will also be marketed to people with CFS. More on the pros and cons of this test kit below.

Hydrogen sulfide is normally found in our bodies at low levels. It is a major part of natural gas (e.g., the gas used in gas ovens). It is usually not toxic at low levels (your body has enzymes to break down small amounts) but can be very toxic at very high levels. The key question is whether the gut bacteria are really producing enough hydrogen sulfide to be a major cause of toxicity. I have not yet been able to find the data on just how high the hydrogen sulfide levels were in Dr. DeMeirleir's study.

To put this in perspective:

  • 0.0047 ppm is the recognition threshold, the concentration at which 50% of humans can detect the characteristic odor of hydrogen sulfide, normally described as resembling "a rotten egg."
  • 2 ppm has been suggested to be associated with subtle medical problems. This is approximately 400 times the level where you will smell it.
  • Less than 10 ppm has an exposue limit of 8 hours per day.
  • 10-20 ppm is the borderline concentration for eye irritation.

This means that you're going to start smelling hydrogen sulfide at less than 100th of the concentration needed for it to be toxic. This means our nose could supply a wonderful and very sensitive test for the presence of hydrogen sulfide overproduction.

Do I Recommend the Hydrogen Sulfide Urine Test?

Not at this time. I think Professor DeMeirleir is a very bright and caring researcher. I would not be surprised if the H2S produced by bowel bacterial overgrowth turns out to be one of many toxins causing problems in CFS. I will be very surprised however if it turns out to be the major cause — as is being proposed in news releases. Basically, I need to see what the actual levels of H2S were that were found in his study and how high a level it takes to give a positive urine test. I hope to see Prof. DeMeirleir at a conference next month and hopefully will be able to get this information from him at that time.

Though the home urine test, when available, will not be very expensive, I am concerned that it will be used to push (scare) people to do other more expensive testing. I prefer to avoid testing that I have not found to be very helpful in guiding people on how to get better.

What Can I Do Now?


I suggest that you use your nose. Increased gas is common in CFS from many causes. Candida overgrowth is usually not associated with its having a foul smell. If your gas smells awful (in layman's terms, "farts that are silent but deadly" — and not always silent), you probably have bacterial overgrowth contributing to your CFS. On the other hand, it doesn't mean it's dangerous. If it did, men in general would be in deep trouble.


This research is fairly new, so I don't think anything different needs to be done yet. The approach below, however, is reasonable if gas that smells like rotten eggs is a part of your symptoms:

  1. Try using Bismuth subsalicylate (BSS). This is commonly known as Pepto Bismol. Each tablespoon or chewable tablet contains 262 mg, and it aggressively soaks up hydrogen sulfide and pulls it out of your body (by turning the hydrogen sulfide into bismuth sulfide). At the same time, it has antibacterial activity that may kill off both the unfriendly bacteria and the biofilms they live in. One to two tablets 3 to 4 times a day will be enough (adjust the dose so that the gas is not too stinky). Give it a 3 to 4 week trial and see if it helps. Then post your results on our community bulletin board and let us know if it helps you. The concern is that the Pepto Bismol may also kill off some of the healthy bacteria, so I would stop it after 3 to 4 weeks. Warning — it is normal for Pepto-Bismol to turn your stools a black color. There appears to be a striking dose-dependent response with BSS: 400 mg / 100 g of dry food completely suppresses cecal hydrogen sulfide release in rats, whereas one fifth of this concentration has no demonstrable effect. What this means in English is just taken enough Pepto-Bismol to keep the flatulence from having a nasty smell.

  2. Similar to bismuth, zinc acetate binds hydrogen sulfide. Zinc deficiency is common and causes immune dysfunction in CFS and fibromyalgia, so taking 25 mg a day of zinc is helpful overall. More than this can be toxic when taken long-term however.

  3. Increase the intake of probiotics (healthy bacteria). I recommend those that come in "pearl form" as otherwise healthy bacteria tend to be destroyed by stomach acid. I recommend probiotic pearls 2 twice a day for five months and then one daily.

Jacob Teitelbaum, MD

is one of the world's leading integrative medical authorities on fibromyalgia and chronic fatigue. He is the lead author of eight research studies on their effective treatments, and has published numerous health & wellness books, including the bestseller on fibromyalgia From Fatigued to Fantastic! and The Fatigue and Fibromyalgia Solution. His newest book (June 10, 2024) is You Can Heal From Long COVID. Dr. Teitelbaum is one of the most frequently quoted fibromyalgia experts in the world and appears often as a guest on news and talk shows nationwide including Good Morning America, The Dr. Oz Show, Oprah & Friends, CNN, and Fox News Health.

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