Always Bloated? Why Your Gut May Be Overgrown & The Medical Steps for SIBO

If you feel bloated almost every day—especially after meals—you're not alone. Many people live with chronic abdominal fullness, pressure, gas, and discomfort and assume it's "just IBS" or something they have to tolerate.

But in some cases, ongoing bloating may be related to SIBO (Small Intestinal Bacterial Overgrowth)—a condition where bacteria grow in the small intestine in higher amounts than normal.

Let's break down what that means, how it happens, and what medical steps are typically taken to diagnose and treat SIBO—based on credible, evidence-based medical guidance.

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What Is SIBO?

SIBO (Small Intestinal Bacterial Overgrowth) happens when bacteria that normally live in the large intestine migrate or overgrow in the small intestine.

The small intestine is not supposed to contain large amounts of bacteria. When it does, those bacteria:

• Ferment food too early
• Produce excess gas (hydrogen or methane)
• Interfere with nutrient absorption
• Trigger inflammation

The result? Persistent bloating, discomfort, and digestive distress.

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Why Does SIBO Cause So Much Bloating?

When you eat carbohydrates—especially fermentable ones—bacteria break them down and release gas.

In SIBO:

• Gas builds up in the small intestine
• The gut stretches and becomes distended
• You may feel pressure or fullness even after small meals

Some people describe it as:

• Looking "pregnant" by evening
• Tightness in the abdomen
• Excess burping or passing gas
• Discomfort that improves overnight and worsens during the day

This isn't just cosmetic bloating. It's often uncomfortable and sometimes painful.

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Common Symptoms of SIBO

Symptoms vary, but commonly include:

• Persistent bloating (often worse after eating)
• Abdominal pain or cramping
• Excess gas
• Diarrhea, constipation, or alternating between both
• Feeling full quickly
• Nausea
• Fatigue
• Brain fog

In more severe or prolonged cases, SIBO may lead to:

• Vitamin deficiencies (especially B12)
• Iron deficiency
• Unintended weight loss

If you're experiencing persistent symptoms and want to understand what might be causing them, using a free AI-powered bloated stomach symptom checker can help you identify potential conditions and prepare informed questions before your doctor's appointment.

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Why Does SIBO Happen?

SIBO usually develops because something slows down or disrupts normal gut movement. The small intestine has a "cleaning wave" (called the migrating motor complex) that sweeps bacteria downward between meals.

If that movement slows, bacteria can accumulate.

Common risk factors include:

• Irritable Bowel Syndrome (IBS)
• Diabetes (especially if nerve damage is present)
• Prior abdominal surgery
• Structural issues (like strictures or adhesions)
• Hypothyroidism
• Celiac disease
• Long-term use of acid-reducing medications
• Conditions affecting gut motility

It's important to understand: SIBO is often a secondary problem. That means something else may be driving it.

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How Is SIBO Diagnosed?

The most common medical test for SIBO is a breath test.

Breath Testing

You drink a sugar solution (usually lactulose or glucose), and then:

• Breath samples are collected over 2–3 hours
• The test measures hydrogen and methane gas
• Elevated levels suggest bacterial overgrowth

There are different types of SIBO:

• Hydrogen-dominant (often associated with diarrhea)
• Methane-dominant (often linked to constipation)
• Mixed type

Breath testing is not perfect, but it's the most widely used non-invasive diagnostic tool.

In rare or complex cases, doctors may perform more advanced testing, but that is uncommon.

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Medical Treatment for SIBO

Treatment generally involves three steps:

1. Antibiotics

The first-line treatment for SIBO is usually antibiotics.

Commonly used medications include:

• Rifaximin (for hydrogen-dominant SIBO)
• Rifaximin + neomycin (for methane-dominant SIBO)

These antibiotics work mostly inside the gut and are minimally absorbed into the bloodstream.

Treatment typically lasts:

• 10–14 days

Many patients notice improvement within weeks. However, recurrence is common, especially if the underlying cause isn't addressed.

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2. Addressing the Underlying Cause

This step is critical.

If SIBO keeps coming back, doctors may evaluate for:

• Thyroid dysfunction
• Diabetes control
• Celiac disease
• Motility disorders
• Structural abnormalities

Sometimes medications that improve gut motility (prokinetics) are prescribed after antibiotics to reduce recurrence.

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3. Diet Modifications

Diet alone usually does not "cure" SIBO, but it may help control symptoms.

Some approaches include:

• Temporary low-FODMAP diet
• Reducing fermentable carbohydrates
• Gradual reintroduction under guidance

It's important not to over-restrict long-term without medical supervision. Overly restrictive diets can:

• Reduce gut diversity
• Worsen nutritional status
• Increase stress around food

Diet should support recovery—not create new problems.

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Can SIBO Be Serious?

In many cases, SIBO is uncomfortable but manageable.

However, you should speak to a doctor immediately if bloating is accompanied by:

• Unintentional weight loss
• Persistent vomiting
• Blood in stool
• Severe abdominal pain
• Difficulty swallowing
• Anemia
• Fever

These symptoms may signal more serious conditions and require urgent evaluation.

Even without red flags, chronic bloating that disrupts daily life deserves medical attention. Don't normalize suffering.

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Why SIBO Often Gets Misdiagnosed

Many people with SIBO are initially told they have IBS. In fact, research suggests a significant percentage of IBS patients may have underlying bacterial overgrowth.

The symptoms overlap heavily:

• Gas
• Bloating
• Altered bowel habits
• Abdominal pain

That's why persistent bloating—especially if it developed after food poisoning, surgery, or illness—should prompt discussion about possible SIBO testing.

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Does SIBO Come Back?

Yes, it can.

Recurrence rates may be significant within 6–12 months if:

• The underlying cause remains untreated
• Gut motility is still impaired
• Structural issues persist

This is not a failure on your part. It's a signal that management may need to go deeper.

Long-term strategies often focus on:

• Supporting gut movement
• Managing contributing medical conditions
• Avoiding unnecessary antibiotics
• Maintaining balanced nutrition

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When to Speak to a Doctor

You should consider discussing SIBO with a healthcare professional if you:

• Feel bloated most days
• Look visibly distended by evening
• Have ongoing IBS-like symptoms
• Have recurrent digestive issues after meals
• Experience unexplained nutrient deficiencies

If you're unsure where your symptoms fall, starting with a free AI-powered bloated stomach symptom checker can help you organize your thoughts before your appointment.

Most importantly:

If anything feels severe, worsening, or associated with warning signs, speak to a doctor immediately. Some abdominal symptoms can indicate serious or life-threatening conditions that need urgent care.

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The Bottom Line

Chronic bloating is not "just in your head." It is not something you simply have to live with.

SIBO is a real, medically recognized condition where bacterial overgrowth in the small intestine can cause:

• Persistent bloating
• Gas
• Pain
• Bowel changes
• Nutrient deficiencies

Diagnosis typically involves breath testing. Treatment usually includes targeted antibiotics, addressing root causes, and thoughtful dietary adjustments.

The key is balance:

• Don't panic.
• Don't ignore it.
• Don't self-treat blindly.

If bloating is constant, uncomfortable, or interfering with your life, it's reasonable—and responsible—to speak to a doctor and ask whether SIBO testing makes sense for you.

Your gut is supposed to work quietly in the background. If it's not, that's worth paying attention to.