Why you've been bloated for weeks — and what actually fixes it

What we checked to reach this conclusion

We reviewed peer-reviewed gastroenterology literature, clinical practice guidelines from the British Society of Gastroenterology and the American College of Gastroenterology, and systematic reviews of dietary and pharmacological interventions for functional bloating and distension. Our standard: we follow the best available evidence, not institutional consensus when the two diverge. On this topic, the evidence and the major clinical guidelines are largely in agreement — FODMAPs and SIBO are the dominant treatable causes that are most often missed by generic advice.

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  Low-FODMAP evidence reviewed Multiple randomised controlled trials confirm that a low-FODMAP diet reduces bloating and distension in the majority of people with functional gut symptoms, with response rates of 50–80% in well-designed studies.
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  SIBO prevalence and diagnosis assessed SIBO is significantly underdiagnosed in people with persistent unexplained bloating; breath testing has a reasonable sensitivity and is the appropriate next step when dietary modification fails, per ACG clinical guidelines.
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  Probiotic evidence scrutinised The evidence for generic over-the-counter probiotics in persistent bloating is weak and inconsistent; strain-specific benefits exist for some conditions but blanket probiotic use is not supported as a primary treatment by current systematic reviews.
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  Red-flag symptom thresholds confirmed Clinical guidelines from NICE and the ACG clearly define the symptoms that require prompt medical investigation rather than self-management — we've reflected these accurately in the guidance below.

Different situations call for different starting points — here's how to choose yours

The right approach depends on whether your bloating is food-driven, bacteria-driven, or has a structural cause — and the only way to know is to test systematically rather than throw supplements at a moving target.

What people try first — and why it keeps failing them

Most people spend weeks cycling through remedies that treat the symptom rather than the cause, which is why they're still bloated weeks later. Here's what the evidence says to skip.

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  Generic over-the-counter probiotics — The evidence for non-specific probiotic supplements in persistent bloating is genuinely weak: a 2021 Cochrane-adjacent systematic review found no consistent benefit across strains for functional bloating, and in SIBO specifically, adding more bacteria to an already overpopulated small intestine can make symptoms worse rather than better.
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  Charcoal tablets and simethicone (Gas-X, etc.) — These products address trapped gas in the colon but do nothing about the upstream fermentation that's producing excess gas in the first place; they may offer brief symptomatic comfort but will not resolve bloating that has persisted for weeks.
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  Eliminating gluten without testing for coeliac disease first — Going gluten-free before having a coeliac blood test (anti-tTG IgA) invalidates the test — your immune response normalises within weeks of stopping gluten, making diagnosis much harder. If coeliac disease is a possibility, get tested while still eating gluten, then adjust your diet based on results.
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  Dramatically increasing fibre intake — "Eat more fibre" is standard digestive advice, but for people whose bloating is driven by FODMAP sensitivity or SIBO, soluble and fermentable fibres — including many found in wholegrains, legumes, and vegetables — are exactly the substances that feed the bacteria causing the problem and will make bloating significantly worse.