SIBO Explained: Symptoms, Causes, and Natural Treatment Options

If you've tried probiotics, cut out gluten, gone low-FODMAP, and still deal with daily bloating, SIBO is worth ruling out. It's more common than most people realise and often gets missed because its symptoms overlap so heavily with general IBS.

What Is SIBO?

SIBO stands for Small Intestinal Bacterial Overgrowth. Normally, the majority of your gut bacteria live in your large intestine, with relatively few in your small intestine. SIBO occurs when bacteria that should be further down your digestive tract overgrow in the small intestine instead, where they ferment food too early and produce excess gas.

Common Symptoms

• Bloating that's often worse than typical IBS, especially shortly after eating
• Excessive gas and belching
• Diarrhoea, constipation, or an alternating pattern of both
• Nutrient deficiencies over time, since overgrown bacteria can interfere with nutrient absorption
• Unintentional weight loss in more severe or long-standing cases

What Causes SIBO?

Slowed gut motility is one of the most common underlying causes, since a properly functioning "migrating motor complex" (the wave-like movement that sweeps bacteria through your gut between meals) normally prevents overgrowth. Other contributing factors include structural issues in the gut, certain medications that slow motility, and previous cases of food poisoning, which can sometimes damage the nerves controlling gut movement.

How SIBO Is Diagnosed

SIBO is typically diagnosed via a breath test that measures hydrogen and methane gas after consuming a test sugar solution. This isn't something to self-diagnose based on symptoms alone, since the treatment approach differs meaningfully from standard IBS management — getting tested properly by a GP or gastroenterologist matters here.

SIBO vs SIFO: A Related but Different Condition

SIFO (Small Intestinal Fungal Overgrowth) is a related condition involving fungal rather than bacterial overgrowth in the small intestine, and can present with very similar symptoms to SIBO. The two are sometimes confused or co-occur, which is another reason proper testing matters rather than assuming symptoms automatically mean bacterial overgrowth specifically.

The Role of the Migrating Motor Complex

Between meals, your gut performs a wave-like cleansing motion called the migrating motor complex, which sweeps bacteria and debris through your digestive tract. This process is disrupted by frequent snacking, since eating resets the cycle before it completes. This is part of why some SIBO management approaches include longer gaps between meals, giving the migrating motor complex time to do its job properly.

Natural and Dietary Approaches

A temporary low-FODMAP diet is often used to reduce the fuel available for bacterial fermentation while other treatment takes effect, though it's generally not recommended as a long-term solution on its own. Herbal antimicrobials (such as oregano oil and berberine) are sometimes used under practitioner guidance as a natural alternative or complement to antibiotic treatment, though the research base is smaller than for pharmaceutical options. Ginger has some evidence supporting gut motility, which may help address the underlying slow-motility issue rather than just the bacterial overgrowth itself.

Supplements That May Help Alongside Treatment

Slippery Elm Bark can help soothe an irritated gut lining while the underlying overgrowth is being addressed, and is generally well tolerated even during active SIBO treatment. L-glutamine is sometimes used afterward to support gut lining repair once the bacterial overgrowth itself has been resolved.

Why Professional Diagnosis Matters

SIBO often requires targeted antibiotic or herbal antimicrobial treatment under professional guidance — diet and supplements alone are rarely enough to fully resolve it, and treating symptoms without addressing the underlying overgrowth tends to lead to relapse. If your bloating pattern matches what's described here, particularly if standard IBS approaches haven't helped, it's worth specifically asking your GP about SIBO testing.

Preventing SIBO Recurrence

SIBO has a notably high recurrence rate after treatment, which is why addressing the root cause — usually the underlying motility issue — matters as much as treating the current overgrowth. Some practitioners recommend a prokinetic (a supplement or medication that supports gut motility) after initial treatment specifically to help prevent the bacteria from building back up in the small intestine.

The Bottom Line

SIBO is a specific, diagnosable condition that's often mistaken for general IBS. Natural approaches like dietary changes and specific herbal supplements can support treatment, but proper diagnosis and, in many cases, targeted antimicrobial treatment are usually necessary for full resolution.