👆 Key takeaways
- SIBO (Small Intestinal Bacterial Overgrowth) is a bacterial overgrowth of the small intestine. Typical symptoms include abdominal pain, bloating, diarrhea or constipation, belching, a feeling of fullness, and heartburn.
- Diagnosis is usually made using a breath test.
- There is no dedicated German AWMF guideline for SIBO. Relevant aspects appear in IBS and intestinal motility guidelines. The ACG guideline (USA, 2020) is the most relevant specific recommendation.
- Nutrition: specific diets (e.g., low-FODMAP, low-fermentation) can be used to support symptom relief.
SIBO Treatment Options According to Guidelines
Contents
1. What is SIBO?
1.1 SIBO and IMO
1.2 SIBO Diagnostics
2. SIBO Treatment
2.1 SIBO Diets
2.1.1 Various SIBO Diets
2.2 SIBO Treatment Without Antibiotics: Herbal Alternatives
2.3 Lifestyle Changes
2.4 Addressing Underlying Causes (PPIs, anatomical issues, motility disorders, etc.)
3. Guidelines for SIBO Treatment
4. Strategies to Maintain Well-Being After SIBO Treatment
5. FAQs
1. What is SIBO?
SIBO stands for “Small Intestinal Bacterial Overgrowth.” SIBO can be associated with symptoms such as 
abdominal pain, bloating, diarrhea, constipation, belching, feeling of fullness, and heartburn, and is caused by an abnormal increase in bacteria in the small intestine. Compared with the colon, which harbors countless microorganisms, a healthy small intestine contains relatively few bacteria. Bacterial overgrowth can overwhelm the small intestine and manifest in the symptoms mentioned.
1.1 SIBO and IMO
If the breath test is positive for methane, this is by definition Intestinal Methanogen Overgrowth (IMO): This means an overgrowth with methane-producing archaea (most commonly Methanobrevibacter smithii), which are archaea in the strict sense. This overgrowth is often accompanied by constipation. Strictly speaking, the term SIBO (“bacterial”) does not apply here, although the therapeutic principles overlap.
1.2 SIBO Diagnostics
For the diagnosis of SIBO, a breath test is typically used, leveraging the fact that human cells produce neither hydrogen nor methane. Methane and hydrogen, however, are produced by bacteria. During the breath test, certain test substances—such as lactulose, glucose, or in specific cases also fructose (1)—are administered. If methane or hydrogen is detected in the breath after a certain period, this indicates the presence of bacteria in the small intestine.
2. SIBO Treatment
There are various treatment options for small-intestinal bacterial overgrowth. These include tailored diets, the use of herbal or conventional antibiotics as well as probiotics (this requires particularly careful selection), and prokinetics. The type of therapy is chosen individually and depends on the predominant microorganisms and the main symptoms present.
2.1 SIBO Diets
Nutrition is a crucial factor in SIBO therapy because it can significantly help to alleviate symptoms. An adjusted diet can help reduce the symptoms of overgrowth in the small intestine and restore balance to the gut flora. However, it cannot reduce bacterial load by itself. Addressing possible nutrient deficiencies is also an important part of a successful SIBO therapy. Various diet models can be used to reduce symptoms in SIBO. The effect of each of these dietary approaches is to deprive bacteria of fermentable substrates and thereby reduce symptoms. These diets can therefore support SIBO therapy but usually need to be combined with other treatments.
2.1.1 Various SIBO Diets
Different nutritional therapies can be used as part of SIBO treatment. These include the low-FODMAP diet, the Specific Carbohydrate Diet (SCD), SIBO-specific food guidelines (SSFG), the Bi-Phasic Diet (BPD), and the low-fermentation diet. Overall, all of these dietary approaches aim to reduce nutrients that can be metabolized by gut bacteria. This slows down gas production by the increased number of bacteria in the gut.
A well-known nutrient source for gut bacteria is FODMAPs. You can learn more about FODMAPs and the low-FODMAP diet here.
The different diet models originate from different individuals. The Specific Carbohydrate Diet was developed by U.S. physician Dr. Haas and focuses on reducing certain grains and carbohydrate sources. Dr. Allison Siebecker developed SIBO-specific dietary guidelines as a combination of the low-FODMAP diet and the SCD. The Bi-Phasic Diet goes back to Dr. Nirala Jacobi and likewise emphasizes avoiding fermentable carbohydrates. The low-fermentation diet was developed by Dr. Pimentel and takes into account not only the types of foods consumed but also meal timing. Dr. Siebecker, Dr. Nirala Jacobi, and Dr. Pimentel have devoted much of their careers to the research, diagnosis, and treatment of SIBO and are considered experts in the field. You can find more information on the individual diet models here.
2.2 SIBO Treatment With and Without Antibiotics, Herbal Alternatives
A mainstay of SIBO therapy is herbal or conventional antibiotics. The goal is always to reduce the problematic bacteria with the help of the antibiotic and thus address the cause—not just the symptoms.
A well-known conventional antibiotic is rifaximin. This antibiotic is particularly suitable for treating hydrogen-dominant overgrowth in the gut because it acts specifically in the gastrointestinal tract. It is not absorbed by the human body and therefore does not enter the bloodstream, acting locally in the intestine. In Germany, however, rifaximin has so far (as of September 2024) only been approved for the treatment of travelers’ diarrhea. This means that the use of rifaximin for treating SIBO is an off-label use and is usually not covered by statutory health insurance. You can find more information about rifaximin in SIBO therapy here. If overgrowth with methane is present, combining rifaximin with metronidazole is possible.
Natural remedies can be a valuable adjunct to SIBO therapy and help relieve symptoms. Many affected individuals benefit from herbal preparations such as oregano oil or garlic, which have antibacterial properties and can inhibit the growth of harmful bacteria in the small intestine. Drinking specific herbal teas, such as peppermint or ginger, can also support digestion and have a soothing effect on the gut.
Bitters (e.g., from gentian, wormwood) activate T2R receptors in the gastrointestinal tract and can, via specific mechanisms, influence gastric acid, motility, and satiety. Clinical data for SIBO are limited; as gentle supporters of intestinal motility (e.g., before meals) they are often used—dose cautiously in reflux/ulcer.
2.3 Lifestyle Changes
Lifestyle changes can have a significantly positive impact in the context of SIBO therapy. Regular exercise promotes intestinal motility and contributes to overall health. Stress management—for example, through techniques such as meditation or yoga—can also contribute positively to treatment success. It is also advisable to ensure adequate fluid intake, as this can support digestion.
2.4 Addressing Underlying Causes (PPIs, anatomical issues, motility disorders, etc.)
The goal of this approach is to prevent relapse by answering the question “Why did SIBO develop?”—and addressing the respective underlying cause. In many cases, this may be a motility disorder or an impaired MMC (migrating motor complex). Prokinetics can sometimes be helpful. As supportive measures: meal spacing (3–4-hour gaps between meals), physical activity, bitters before meals. The use of proton-pump inhibitors (PPIs) should then be critically reviewed. If medically feasible, they should be reduced and discontinued in the long term. The goal is to restore the body’s own gastric acid as a barrier to microbes and to re-establish healthy digestive processes.
If SIBO has developed due to specific anatomical adhesions or irregularities, these should be clarified and treated if possible. It is also important to identify and treat other conditions that frequently coexist with SIBO, such as endometriosis, hypothyroidism, pancreatic insufficiency, etc.
3. Guidelines for SIBO Treatment
At present, there is no official German AWMF (Association of the Scientific Medical Societies in Germany) guideline specifically for the treatment of SIBO. However, small-intestinal bacterial overgrowth is discussed in other German guidelines, especially in the guideline on irritable bowel syndrome (IBS) (2) and in the guideline on intestinal motility disorders (3).
The American College of Gastroenterology (ACG) publishes guidelines for the U.S. setting. There is also a guideline on IBS (4), and since 2020 there has been a dedicated guideline on SIBO (5).
The ACG guideline recommends treating symptomatic patients with antibiotics to eradicate the overgrowth. A diet low in fermentable components can be helpful in SIBO therapy, as can the use of specific probiotics. However, probiotic use requires therapeutic guidance. Many probiotics are not suitable in the acute phase. Overall, the number of strong treatment recommendations remains limited. SIBO is an area that still requires substantial research (as of 09/2024). Nevertheless, many physicians and practitioners report good practical experience with certain treatment approaches and, in addition to the guidelines, are guided by their clinical experience.
4. Strategies to Maintain Well-Being After SIBO Treatment
To achieve long-term success with SIBO treatment, maintain well-being over time, and prevent relapse, it is essential to develop individual strategies. As with treatment itself, nutrition is key. It may seem counterintuitive, but a diet that supports long-term gut health is one rich in fiber, probiotic foods, and prebiotic ingredients. During SIBO therapy the focus is on reducing symptoms and eradicating harmful bacteria, which is why fiber and FODMAPs are often restricted. Once the gut environment has been restored, however, it is important to maintain it. Fiber and FODMAPs are then needed again, as they serve as a nutrient source especially for beneficial gut bacteria. It is also advisable to avoid highly processed foods, sugar, and alcohol, as these can promote the growth of harmful bacteria.
Regular physical activity, stress management through techniques such as meditation or yoga, and sufficient sleep also play an important role in maintaining a healthy gut. In addition, in the case of persistent or recurrent symptoms, regular medical check-ups should be considered to allow early intervention.
5. FAQs
What is SIBO and what symptoms occur?
SIBO (“Small Intestinal Bacterial Overgrowth”) is a bacterial overgrowth of the small intestine. Common symptoms include abdominal pain, bloating, diarrhea or constipation, belching, a feeling of fullness, and heartburn.
How is SIBO diagnosed?
Typically via breath testing: after administering substrates (e.g., lactulose, lactose, glucose, fructose), detection of hydrogen or methane in the breath provides evidence of bacterial overgrowth in the small intestine.
What treatment options are available?
Therapy is individualized and may include nutritional therapy (e.g., low-FODMAP, SCD, SSFG, Bi-Phasic Diet, low-fermentation diet), herbal or conventional antibiotics (e.g., rifaximin; off-label for SIBO in Germany), and, where appropriate, probiotics. Lifestyle factors such as exercise, stress management, and adequate fluid intake provide additional support.
Are there guidelines for SIBO treatment?
In Germany there is currently no standalone AWMF guideline exclusively for SIBO; relevant recommendations can be found in the guidelines on irritable bowel syndrome (IBS) and intestinal motility disorders. In the USA there has been a SIBO guideline from the American College of Gastroenterology (ACG) since 2020, which recommends antibiotics for symptomatic patients; diets low in fermentable components and probiotics can be supportive. Overall the evidence is still limited (status: 09/2024)
References
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