Probiotics and SIBO

Probiotics may support SIBO recovery by helping reduce bacterial overgrowth, easing bloating, and improving digestion. Research suggests they can be effective when tailored to your SIBO type and used as part of a structured treatment plan.

If you’re living with Small Intestinal Bacterial Overgrowth (SIBO), you’ll know how frustrating the symptoms can be: bloating that never seems to go away, irregular bowels, fatigue, and the constant guessing game around what foods your gut will tolerate. Managing SIBO can feel overwhelming, especially when advice online often seems conflicting.

One area getting more attention in recent years is the role of probiotics. Research suggests that certain probiotic strains may help reduce the number of bacteria in the small intestine, ease digestive discomfort, and support the restoration of a healthier gut balance.

In this article, we’ll explore the evidence behind probiotics and SIBO, highlight the strains showing the most promise, and explain how the right support, from accurate testing to expert-led programmes on how to treat SIBO at home, can help you take back control of your gut health.

Read our article SIBO and Ulcerative Colitis: Treatment and Connection if you are looking for more information on the relationship between the two conditions and effective treatments.

Understanding the Link Between Probiotics and SIBO

If you’ve been dealing with ongoing bloating, discomfort after meals, or unpredictable digestion, you may have come across the term Small Intestinal Bacterial Overgrowth (SIBO). In simple terms, SIBO happens when there are too many bacteria living in the small intestine – an area that’s normally meant to have relatively low levels of bacteria. When this balance is disrupted and the bacteria exceed 10⁵ CFU/mL, it can interfere with digestion and cause a wide range of symptoms [1].

For many people, this can mean persistent bloating, abdominal pain, irregular bowels, fatigue, and even nutrient deficiencies like low vitamin B12 or iron [2]. Over time, these issues can take a toll on both your digestion and your overall well-being.

SIBO can develop for different reasons. Sometimes it’s linked to slower gut motility, reduced stomach acid, or previous abdominal surgery. In other cases, hormonal changes, stress, or other digestive conditions can play a role [3]. Because there’s no one-size-fits-all cause, the best management plans are usually personalised and aim to restore balance to the gut rather than just masking symptoms.

This is where probiotics come in. These are live, beneficial microorganisms that can support a healthier gut environment when taken in the right way [4]. Recent research suggests that probiotics may help reduce bacterial overgrowth in the small intestine, ease digestive symptoms, and support better long-term outcomes.

For example, a 2017 meta-analysis found that probiotics achieved a 62.8% SIBO decontamination rate and were linked to a 36.35 ppm reduction in hydrogen levels – a sign of less fermentation and improved gut function [5]. Other studies show that combining certain probiotics with antibiotic treatment can improve results even further. One trial using Lactobacillus casei alongside rifaximin found that participants reported significantly greater relief from bloating and abdominal pain compared to antibiotics alone [6].

That said, it’s important to remember that probiotics aren’t right for everyone. In a small number of cases, some people report increased bloating, gas, or discomfort after starting them [7]. That’s why it’s always best to approach probiotic use with personalised guidance, especially if you’re managing complex symptoms.

How Probiotics May Help Improve SIBO Symptoms

When you’re living with SIBO, symptoms like bloating, irregular bowels, fatigue, and food sensitivities can make everyday life frustrating. Probiotics are thought to help by gently restoring balance in the gut and reducing the effects of bacterial overgrowth in the small intestine.

Certain probiotic strains may work in several ways. They can help reduce gas production by limiting the growth of bacteria that ferment carbohydrates, which in turn may ease bloating and discomfort [8]. Some probiotics also produce natural compounds that reduce the presence of harmful bacteria and improve the environment of the small intestine, supporting more regular bowel movements and better digestion overall.

Probiotics may also play a role in calming the immune response and strengthening the gut lining, which can make it easier to tolerate a wider variety of foods [9]. Over time, these combined effects can support better energy levels and help manage common SIBO-related issues like food sensitivities and fatigue.

It’s important to remember, though, that not all probiotics are the same. The benefits largely depend on choosing the right strains and dosage, ideally with personalised guidance, to match your SIBO type and symptoms.

What Research Says About Probiotics for SIBO

Research into the role of probiotics in managing Small Intestinal Bacterial Overgrowth (SIBO) has grown significantly in recent years, and the findings are promising for many people struggling with ongoing symptoms. While treatment approaches often include dietary changes, supplements, and sometimes antibiotics, there’s increasing evidence that probiotics can play a valuable role in supporting recovery.

One 2017 meta-analysis looked at multiple clinical trials and found that probiotics achieved a 62.8% SIBO decontamination rate [10]. This means that in nearly two-thirds of participants, the presence of excessive bacteria in the small intestine was significantly reduced. Importantly, the same study reported a 36.35 ppm drop in hydrogen levels, a key marker used in SIBO breath testing to measure fermentation levels in the gut. A decrease of this size suggests that probiotics can help reduce gas production, bloating, and other symptoms associated with bacterial overgrowth.

Other studies support these findings, showing that certain probiotic strains not only reduce bacterial counts but may also improve digestive comfort and bowel regularity [11]. In some cases, probiotics have been shown to work alongside antibiotic therapy to enhance treatment outcomes. For example, using Lactobacillus casei or Bacillus clausii alongside rifaximin has been linked to greater symptom relief than antibiotics alone [12].

It’s worth noting, though, that the effectiveness of probiotics can vary depending on the type of SIBO (hydrogen-dominant, methane-dominant, mixed, or sulphide-producing) and the specific strains used. This highlights the importance of choosing the right approach, ideally with practitioner guidance, to match your symptoms and SIBO profile.

Key Probiotic Strains That Show Promise

Not all probiotics work the same way, and when it comes to SIBO, choosing the right strains can make a big difference. Research so far suggests that a few key options may help reduce bacterial overgrowth, improve gut balance, and ease symptoms when used as part of a structured treatment plan.

Saccharomyces boulardii

Saccharomyces boulardii is a beneficial yeast rather than a traditional bacterial probiotic. Unlike many bacterial strains, it isn’t affected by standard antibiotics, which means it can often be used alongside treatments like rifaximin without being destroyed in the process. It’s thought to work by supporting healthy immune responses, limiting the growth of harmful bacteria, and helping to restore balance in the gut environment [10]. Many people with SIBO find this strain useful because it may reduce bloating and diarrhoea while helping to strengthen the intestinal lining.

Bacillus clausii

Bacillus clausii is a spore-forming probiotic, which means it can survive the journey through stomach acid and reach the small intestine intact. It’s known for producing natural antimicrobial compounds that can help suppress the growth of harmful bacteria and create a more balanced gut environment [12]. Clinical studies suggest that Bacillus clausii may work particularly well when used alongside antibiotic treatment, making it a valuable option for supporting both bacterial decontamination and symptom relief.

Selected Lactobacillus Strains

Certain strains within the Lactobacillus family, such as L. plantarum and L. rhamnosus, are being explored for their role in improving SIBO symptoms. These probiotics may help by producing compounds like lactic acid, which reduce the pH of the gut environment, making it harder for harmful bacteria to thrive [10]. They may also support better gut motility and help ease constipation or irregular bowel patterns, which are common in methane-dominant and mixed-type SIBO.

Sourcing These Probiotics

These probiotics are available in the UK through a range of high-quality supplements, including practitioner-recommended brands that ensure accurate strain selection and effective dosages. Because SIBO treatment often needs to be tailored to your test results and symptoms, it’s best to speak with a qualified nutritionist or functional medicine practitioner before choosing a supplement. At IBS Clinics, private consultations are available to help you select the right probiotics based on your SIBO type and integrate them safely into your wider recovery plan.

Should Everyone With SIBO Take Probiotics?

While probiotics can be helpful for many people with Small Intestinal Bacterial Overgrowth (SIBO), they’re not always the right approach for everyone. The way your gut responds can depend on factors such as the type of SIBO you have, your overall gut health, and how your body reacts to certain probiotic strains.

For some people, the right probiotics can support bacterial balance, reduce bloating, improve bowel regularity, and help strengthen the gut lining [10]. However, in other cases, probiotics can worsen symptoms, especially when the wrong strains are used or when introduced too quickly. Some people experience increased bloating, gas, or abdominal discomfort, which may indicate that a different approach or dosage is needed [12].

One key factor is your SIBO type. There are four main subtypes, and choosing the right probiotics often depends on which one you have:

Hydrogen-dominant SIBO – Often linked to diarrhoea and bloating. Certain Lactobacillus and Saccharomyces boulardii strains may help reduce hydrogen production and improve stool consistency.
Methane-dominant SIBO (now called IMO — Intestinal Methanogen Overgrowth) – Typically associated with constipation, and may require a carefully chosen combination of probiotics to avoid worsening gas production.
Mixed-type SIBO – Involves both hydrogen and methane overproduction. This subtype can require a more personalised approach combining targeted probiotics and dietary support.
Sulphide-dominant SIBO – A less common form involving hydrogen sulphide production, often linked with foul-smelling gas and food sensitivities. Here, caution with probiotics is especially important, and practitioner guidance is strongly advised.

Because each SIBO type behaves differently, personalised treatment is key. Working with a nutritionist or functional medicine practitioner can help you identify the right strains, dosage, and timing based on your breath test results and symptoms.

The Role of Testing Before Starting Probiotics

Before starting probiotics, it’s important to understand what’s happening in your gut. A SIBO breath test is one of the most valuable tools for identifying whether SIBO is present and, if so, what type you have.

The breath test measures hydrogen and methane levels after drinking a specific sugar solution. High readings indicate that bacteria in the small intestine are fermenting these sugars too quickly, which is a sign of bacterial overgrowth. Crucially, the results also help determine whether you have hydrogen-dominant, methane-dominant, mixed-type, or sulphide-producing SIBO. Knowing your subtype is key to tailoring treatment, as different probiotics, supplements, and dietary strategies work better for different types [10].

Alongside breath testing, there are also at-home tests that can provide a fuller picture of your digestive health:

Stomach acid (HCl) function tests – Low stomach acid can make it easier for bacteria to build up in the small intestine. Simple at-home assessments, like the HCl titration test, can help you understand whether stomach acid levels might be contributing to your symptoms.
Enzyme function checks – Poor pancreatic enzyme output can impair digestion and create an environment where SIBO is more likely to develop. Testing enzyme function can highlight whether additional digestive support might be beneficial.
Bile flow assessments – Since bile naturally helps regulate bacterial growth, measuring its function can be useful for understanding why SIBO may have developed in the first place.

By combining these tools, you can make better-informed decisions about whether probiotics are suitable, which strains to choose, and what additional steps may be needed to restore balance in your gut. At IBS Clinics, testing is often the first step before designing a personalised treatment plan, ensuring any probiotics or supplements are carefully matched to your results and symptoms.

How IBS Clinics Can Support Your SIBO Recovery

Managing SIBO can feel overwhelming, especially when you’re trying to make sense of conflicting information online. At IBS Clinics, we aim to make the process simpler by combining expert guidance, practical tools, and evidence-based strategies to help you restore balance and feel more in control of your gut health.

One of the most effective ways we support clients is through the “I Can Beat SIBO” online programme – a 6-module, practitioner-led course designed to help women beat chronic bloating, irregular bowels, fatigue, and food sensitivities by addressing the root causes of Small Intestinal Bacterial Overgrowth.

This structured 8-week programme includes:

Practitioner-led guidance – Learn directly from experts who specialise in SIBO treatment and recovery.
Tailored food plans – Nutritional strategies customised to your SIBO type (hydrogen, methane, mixed, or sulphide) using UK-friendly ingredients.
Supplement and testing strategies – Step-by-step guidance on targeted supplementation and home testing, including HCl titration and enzyme checks.
Hormone-aware symptom tracking – Tools designed specifically for women, helping you understand how hormonal changes affect digestion.
Downloadable trackers and meal plans – Practical, easy-to-use resources for tracking your symptoms, supplements, and progress.

The course is self-paced and flexible, so you can move through it at your own speed while still having a structured plan to follow. It’s designed to be practical, empowering, and supportive without being overwhelming.

In addition to the programme, IBS Clinics also offers private one-to-one consultations with experienced nutritionists and functional medicine practitioners. These sessions provide a chance to tailor your treatment plan even further – from selecting the right probiotics to managing your food plan, supplements, and ongoing testing based on your unique needs.

Whether you want step-by-step support through the online course, personalised guidance through private consultations, or a combination of both, IBS Clinics can help you build a recovery plan that works for your lifestyle.

Next Steps to Take Control of Your Gut Health

Living with SIBO can be challenging, but the right approach can make a real difference. Research shows that probiotics may support small intestine decontamination, reduce fermentation, and help ease common symptoms like bloating, fatigue, and irregular bowels [10]. While they aren’t suitable for everyone, when carefully chosen and used alongside a personalised plan, probiotics can be an important tool for restoring gut balance and improving overall digestive health.

If you suspect you have SIBO or want to explore treatment options, the first step is understanding what’s happening in your gut. A SIBO breath test can help identify your specific SIBO type and guide a tailored treatment plan designed for your needs.

At IBS Clinics, we provide several ways to support you:

The SIBO breath test – Gain clear insights into your SIBO type and bacterial activity levels.
The “I Can Beat SIBO” online programme – A structured, practitioner-led approach to managing SIBO with tailored food plans, supplements, and practical tools.
Private consultations – One-to-one support with experienced nutritionists and functional medicine practitioners to create a recovery plan that works for your lifestyle.

Taking control of SIBO starts with getting the right information, a structured plan, and expert support. Whether you’re just beginning your journey or looking for a more targeted treatment, IBS Clinics can help you take the next step towards better gut health.

References

Quigley, E.M.M., & Quera, R. (2006). Small intestinal bacterial overgrowth: Roles of antibiotics, prebiotics, and probiotics. Gastroenterology, 130(2), S78–S90. https://pubmed.ncbi.nlm.nih.gov/16473078
Rezaie, A., Buresi, M., Lembo, A., et al. (2017). Hydrogen and Methane-Based Breath Testing in Gastrointestinal Disorders: The North American Consensus. American Journal of Gastroenterology, 112(5), 775–784. https://pubmed.ncbi.nlm.nih.gov/28323273
Ghoshal, U.C., Shukla, R., & Ghoshal, U. (2017). Small intestinal bacterial overgrowth and irritable bowel syndrome: A bridge between functional organic dichotomy. Gut and Liver, 11(2), 196–208. https://pubmed.ncbi.nlm.nih.gov/28074702
Hill, C., et al. (2014). The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 11(8), 506–514. https://pubmed.ncbi.nlm.nih.gov/24912386
Zhong, C., Qu, C., Wang, B., & Liang, S. (2017). Probiotics for Preventing and Treating Small Intestinal Bacterial Overgrowth: A Meta-analysis and Systematic Review. Journal of Clinical Gastroenterology, 51(4), 300–311. https://pubmed.ncbi.nlm.nih.gov/28267052
Gabrielli, M., Lauritano, E.C., Scarpellini, E., et al. (2009). Bacillus clausii and rifaximin in SIBO treatment: Efficacy and tolerability. Alimentary Pharmacology & Therapeutics, 29(5), 552–560. https://pubmed.ncbi.nlm.nih.gov/19183154
Rao, S.S.C., Rehman, A., Yu, S., & Andino, N.M. (2018). Brain fogginess, gas and bloating: A link between SIBO, probiotics and metabolic acidosis. Clinical and Translational Gastroenterology, 9(6), 162. https://pubmed.ncbi.nlm.nih.gov/29904186
Zhong, C., Qu, C., Wang, B., & Liang, S. (2017). Probiotics for Preventing and Treating Small Intestinal Bacterial Overgrowth: A Meta-analysis and Systematic Review. Journal of Clinical Gastroenterology, 51(4), 300–311. https://pubmed.ncbi.nlm.nih.gov/28267052
Hill, C., et al. (2014). The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 11(8), 506–514. https://pubmed.ncbi.nlm.nih.gov/24912386
Zhong, C., Qu, C., Wang, B., & Liang, S. (2017). Probiotics for Preventing and Treating Small Intestinal Bacterial Overgrowth: A Meta-analysis and Systematic Review. Journal of Clinical Gastroenterology, 51(4), 300–311. https://pubmed.ncbi.nlm.nih.gov/28267052
Ghoshal, U.C., Shukla, R., & Ghoshal, U. (2017). Small intestinal bacterial overgrowth and irritable bowel syndrome: A bridge between functional organic dichotomy. Gut and Liver, 11(2), 196–208. https://pubmed.ncbi.nlm.nih.gov/28074702
Gabrielli, M., Lauritano, E.C., Scarpellini, E., et al. (2009). Bacillus clausii and rifaximin in SIBO treatment: Efficacy and tolerability. Alimentary Pharmacology & Therapeutics, 29(5), 552–560. https://pubmed.ncbi.nlm.nih.gov/19183154

Author – Tracey Randell

At IBS Clinics, Tracey Randell, a renowned Nutritional Therapist and one of the few IFM Certified Practitioners in the UK, extends her specialised knowledge and unique approach to managing and treating IBS and other gut-related conditions effectively.

Tracey’s profound understanding of Functional Medicine allows her to connect the dots for complex health conditions, identifying and addressing the root causes to curate personalised and comprehensive health plans for her patients. Her holistic approach focuses on resolving underlying imbalances and optimising gut health, enabling the body to correct other issues and attain overall well-being.

At IBS Clinics, we are dedicated to being your partner in navigating your gut-related health concerns, offering expert care and individualised treatment plans to alleviate your IBS symptoms and enhance your quality of life.

DISCLAIMER: The information provided in this article is intended for general informational purposes only and should not be construed as medical advice, diagnosis, or treatment. The products and methods mentioned are not a substitute for professional medical advice from a trained healthcare specialist. Always seek the guidance of your doctor or other qualified health professional with any questions you may have regarding your health or a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. Use of the information and products discussed is at your own risk.