Endometriosis and the SIBO connection

SIBO and endo


Endometriosis and Small Intestinal Bacterial Overgrowth (SIBO) unfortunately seem to go hand in hand. Recent research has shown that up to 92% of endometriosis patients with digestive issues test positive for SIBO. This link is commonly driven by pelvic inflammation, adhesions, and slowed gut motility, which create an ideal environment for bacterial overgrowth.

Many women with endometriosis often think they have IBS, but 84% of IBS cases are actually SIBO. Additionally, 50% of women with SIBO have Leaky Gut.

A case-control study from 2025 International Federation of Gynecology and Obstetrics showed results that SIBO prevalence was significantly higher among women with endometriosis, with up to 136 out of 148 who tested positive. Conclusion to the research was that abnormal digestive overgrowth should be assessed in all endometriosis cases, as this approach could offer a new therapeutic strategy.

What is SIBO                                   

Small intestinal bacterial overgrowth (SIBO) is a serious condition affecting the small intestine. It occurs when bacteria that normally grow in other parts of the gut start growing in the small intestine.  While bacteria naturally occur throughout the digestive tract, in a healthy system, the small intestine has relatively low levels of bacteria.

If left untreated it can lead to problems of malabsorption of nutrients, especially fat-soluble vitamins like vitamin A and D and iron.  As women with endometriosis can easily become low in iron due to having heavy periods, having depleted iron levels can make you feel quite ill and very weak and fatigued.

Having a weaken immune system and abdominal surgery can be underlying causes of developing SIBO, as well as damage to the nerves and muscles of the gut can increase your risk.  Low stomach acid can be another risk factor along with a diet high in sugar and processed carbs.

SIBO symptoms mainly affect the gut

One of the notable symptoms is a bloated and distended stomach which may be mistaken as endo-belly, which in itself is very common, and usually happens during an endometrioses flare.  The bloating of SIBO is caused by gas produced from fermentation in the small intestine, triggered by the bacteria as it feasts on food in the gut.  This process can build up as the day goes on and by the end of the day your belly can be very distended and painful accompanied by gas.

Other symptoms of SIBO include:

  • Diarrhoea – Usually associated with hydrogen dominant SIBO
  • Constipation – usually associated with methane dominant SIBO
  • Alternating constipation and diarrhoea
  • Gas, Flatulence, Belching, Severe Bloating
  • Abdominal pain and cramps
  • Leaky gut – Intestinal permeability
  • Weight loss or gain
  • Food sensitivities
  • Headache
  • Chronic Fatigue syndrome
  • Fibromyalgia
  • Lactose intolerance, Fructose intolerance, Sucrose intolerance
  • Iron and B12 deficiency
  • Fatigue
  • Nausea


Getting tested

A breath test is a common test for diagnosing SIBO. Excess bacteria in the small intestine can lead to the release of the gases hydrogen and methane, which can be identified through a breath test. The test can be performed at home or at your doctor’s office.

You’ll need to fast overnight before having a breath test. During the test, you’ll breathe into a tube. You will then drink a special sweet drink provided by your doctor. You will breathe into a series of additional tubes at regular intervals for 2 to 3 hours after consuming the drink.

Other tests include a stool test and blood test may be used to check for nutrient deficiencies.

Treatment of SIBO

1. Antibiotics

The antibiotic Rifaxamin is considered the number 1 antibiotic choice for hydrogen or Methane dominant SIBO and is often combined with neomycin which is an antibiotic that fights bacteria in the body

2. Antimicrobials

A range of different natural plant-based antimicrobials have been found to be as effective against SIBO as the antibiotics and these can also impact on SIFO (small intestine fungal overgrowth).

3. Diet

- The elemental diet involves consuming a drink that provides all of your daily nutrient needs but doesn’t feed the bacteria.

- Studies show the elemental diet helps to eradicate SIBO in 85% of people.

- Basically, it has been shown that the elemental diet is one of the most effective treatment options for patients suffering from a variety of digestive conditions, particularly those struggling with small intestinal bacterial overgrowth (SIBO) symptoms.

- Very simply, the elemental diet is a liquid formula (usually in powdered form) that contains all the essential nutrients humans need to live broken down into their simplest forms so they are easily absorbed.

Types of Nutrients Included:

  • Carbohydrates in the form of monosaccharides
  • Proteins in the form of amino acids
  • Fats in the form of fatty acids
  • Essential vitamins and minerals

By eliminating the need for the GI systems of those with SIBO to perform normal digestive functions, as well as limiting the fuel source for bacteria, the elemental diet acts as a protective way to ensure that you still consume all the necessary nutrients during the treatment period while allowing the bowels to rest and decreasing bacterial overgrowth.

You can find more details about the elemental diet here:

https://www.siboinfo.com/elemental-formula.html


Many are able to manage and control SIBO with herbal antimicrobials

The use of single antimicrobials and the use of broad-spectrum antimicrobials have both been used successfully. Some common herbs used in SIBO treatment include oil of oregano, allicin, berberine herbs, and neem. The treatment duration with herbal antimicrobials is typically longer than with antibiotics.

Allicin - found in garlic taken as capsules

Berberine - consists of a compound found in Oregon grape, barberry, goldenseal, and other herbs.

Neem - This comes from the tropical evergreen Neem Tree, which has helped with health conditions from diabetes to heart disease. Neem, used in conjunction with Berberine, helps boost the immune system.

Oregano - Oil of Oregano is a natural, powerful antibiotic, which is why it is often used to treat SIBO.  Oregano oil is also use to treat candida.

Wormwood - Wormwood possesses several medicinal compounds which include anti-inflammatory, antimicrobial, and antioxidant properties. Wormwood can help in the treatment protocol for SIBO.

Indian Barberry Root - The bark of the trunk and root is known for its medicinal uses as it contains alkaloids that assist in a number of bodily functions, especially of the digestive track.

To sum up treatment

You need to be consistent with your treatment plan and then retest again.  Sometimes it can take up to 3 to 4 rounds of treatment to get on top of SIBO as it can be a tough cookie to deal with. 

SIBO can sometimes become serious and can often be misdiagnosed as IBS.  Untreated, SIBO can lead to chronic inflammation, gut issues, and the development of auto-immune conditions.  The natural treatment protocol for SIBO is diet, probiotics, and taking digestive enzymes with every meal to increase your stomach acids.

If you have been tested for SIBO and start treatment you may feel a bit rough with ‘die-off’ symptoms, but this usually only occurs if you are undergoing drastic treatment like taking potent anti-microbials or making big diet changes. 

Symptoms will typically include flu-like symptoms, headache, brain-fog, constipation and other digestive upset.  This will pass as the treatment progresses and symptoms will gradually improve.  Although these symptoms are not ideal, it is actually an indication that that the treatment is working.

Final word …..

Discovering if you have SIBO as well as endometriosis can prove really vital to help you resolve some of your symptoms. It will show that not all your pain and discomfort is due simply to endometriosis and will highlight that a lot of your abdominal distress is actually caused by SIBO. By doing a simple, non-invasive breath-test with the help of your GP is really worth pursuing especially as the symptoms can be really distressing and SIBO can further undermine your health by depleting vital nutrients that your body needs.


Testing for SIBO UK

https://smartsibotest.com

Testing for SIBO USA

https://sibotest.com/pages/index

Comprehensive list of SIBO testing laboratories for USA, UK, Australia

https://www.siboinfo.com/testing.html

Step by step SIBO treatment plan

https://sibosos.com/sibo-recovery-roadmap/

Sources:

https://pubmed.ncbi.nlm.nih.gov/39959963/

https://www.medicalnewstoday.com/articles/endometriosis-and-sibo

https://endometriosis.net/clinical/ibs-sibo

https://pmc.ncbi.nlm.nih.gov/articles/PMC10458414/

https://endometriosis.net/living/endo-belly-remedies


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About the Author

Hi, I am Carolyn Levett, the Founder here at endo-resolved - I am an Integrative Health Coach having studied nutrition, naturopathy and aromatherapy as well as being a published author of three endometriosis books. I used to suffer from severe endometriosis and was fortunate to be able to regained my health and recover from this disease with the support of nutrition, natural therapies and lots of determination.

My motivation is to help other women with endometriosis to heal their bodies so they may start to overcome this awful disease without having to totally rely on toxic drugs and surgeries which can cause further damage  -  with healing thoughts, Carolyn.

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