SIBO:Symptoms,Treatment & Test

By Amy Burkhart MD, RD

Bloating that won’t go away. Stomach pain after eating. Unpredictable digestion. These are common SIBO symptoms. If you’ve been struggling with frustrating gut issues and can’t find answers, small intestinal bacterial overgrowth (SIBO) might be the culprit. But what exactly is SIBO?

How do you know if you have it? Could it be the reason your IBS treatments aren’t working? Is there a reliable SIBO test? And most importantly—what can you do to start feeling better?

Let’s dive into everything you need to know about SIBO, its symptoms, and how the right approach—including diet—can help you take control of your gut health.

SIBO stands for small intestinal bacterial overgrowth

Small Intestinal Bacterial Overgrowth (SIBO) happens when too many bacteria take over the small intestine. This overgrowth disrupts digestion, making it harder for your body to absorb nutrients and leading to frustrating SIBO symptoms like bloating, diarrhea, constipation, and even fatigue. We need gut bacteria to live. They are vital to maintaining health. But, they cause problems if they aren’t where they are supposed to be.

Understanding SIBO symptoms is the first step toward getting the relief you need.

The most common symptom of SIBO is bloating.

When someone has SIBO, the bacteria ferment the sugars/carbohydrates a person eats and produce gas. This results in the person feeling bloated. Think of a jar of sauerkraut—fermented cabbage. When you first open it, you hear a hiss as trapped gas escapes from the pressure inside. A similar process happens in your gut when you have SIBO, causing that tight, bloated feeling. Symptoms differ from person to person but bloating is the most common SIBO symptom.

Common SIBO Symptoms

• Bloating – A frequent and uncomfortable feeling of fullness or swelling in the abdomen
• Gas – Excessive burping or flatulence caused by bacterial fermentation
• Stomach pain – Cramping or discomfort, often after eating
• Diarrhea – Loose or frequent bowel movements
• Constipation – Difficulty passing stools, sometimes alternating with diarrhea
• Weight loss – Unintentional weight loss due to poor nutrient absorption
• Fatigue – Feeling tired or sluggish, even after rest
• Nausea – A queasy or unsettled stomach
• Headaches-Migraines are more common in SIBO
• Nutrient deficiencies – Symptoms related to poor absorption of essential nutrients, including:
  • Vitamin B12, A, D, E, and iron – Can cause fatigue, weakness, and neurological issues
  • Other B vitamins – May lead to brain fog, low energy, and skin problems
  • Fat, protein, and carbohydrate malabsorption – Can contribute to weight loss, digestive issues, and muscle weakness
• Carbohydrate intolerance – Symptoms like bloating, pain, gas, and fatigue after eating carbs
• Joint pain – Unexplained aches and inflammation
• Depression & Anxiety – Mood changes linked to gut health imbalances
• Rashes– May occur; Histamine intolerance is more common in SIBO

🛑 Important Note: Many other conditions can mimic SIBO symptoms, and SIBO can also occur alongside other health issues. A proper diagnosis is key to finding the right treatment.

There is more than one cause of SIBO

To keep your gut healthy and lower the risk of SIBO, your digestive system needs to function correctly. The following are factors that influence a person’s risk of SIBO.

• Healthy stomach acid levels – Long-term use of acid-blocking medications can increase the risk of SIBO.
• Proper intestinal motility – The digestive system must move food efficiently through the intestines to prevent bacteria from building up where they shouldn’t be. Blockages, abnormal gut motility and even stress can affect gut motion.
• A strong intestinal lining – Conditions like celiac disease, inflammatory bowel disease, and leaky gut can weaken the gut lining, increasing the risk of SIBO.
• A well-functioning pancreas and gallbladder – These organs help break down food and support digestion. When they don’t work properly, it can contribute to bacterial overgrowth.
• Healthy intestinal valves – Think of these valves as “doors” in your digestive tract that open and close at the right times. If they aren’t working correctly, bacteria can end up in the wrong place, leading to problems like SIBO.

If a person has one of these conditions, they have a higher risk of having SIBO:

How Is SIBO diagnosed?

When people talk about a SIBO test, they’re usually referring to the hydrogen breath test. This simple, non-invasive test works like this:

1. You drink a sugar-containing solution.
2. Your breath is analyzed for gases like hydrogen, methane, and sulfur. ( See Video below explaining the test)
3. If too many bacteria are present in the small intestine, they ferment the sugar and release excess gas, which can be detected in your breath.

While convenient, breath tests aren’t perfect—they have an accuracy rate of about 65-70%. Because of this, some practitioners diagnose and treat SIBO based on symptoms alone. However, this approach isn’t ideal since SIBO symptoms overlap with many other conditions.

For the best diagnosis and treatment, it’s important to work with a knowledgeable healthcare provider who understands SIBO, recognizes key clinical clues, and knows the strengths and limitations of breath testing.

📝 Note: A more direct method involves taking a fluid sample from the small intestine, but this is rarely done in routine practice.

The Link Between SIBO, Celiac and Gluten Sensitivity

Research shows that SIBO is more common in celiac patients who continue to have symptoms despite following a gluten-free diet.

There also seems to be a higher incidence of SIBO in people with non-celiac gluten sensitivity (NCGS), though no formal studies have confirmed this link yet. As research on this topic continues to evolve, new connections may emerge.

Interestingly, many cases of gluten sensitivity are actually due to FODMAP intolerance, which is best managed with a low FODMAP diet. Since the low FODMAP diet helps IBS, and IBS is strongly linked to SIBO, the connection between gluten issues and SIBO is becoming clearer—just not officially documented in research yet.

Irritable Bowel Syndrome (IBS) Overview

Irritable bowel syndrome (IBS) is a common condition that causes symptoms like:

• Bloating
• Cramping
• Abdominal pain
• Diarrhea and/or Constipation

There’s no definitive test for IBS. Instead, diagnosis is based on your symptoms and medical history. As our understanding of IBS grows, debates about its causes and treatments are likely to continue.

The Connection Between IBS and SIBO

Some studies suggest that 50-70% of people with IBS may actually have SIBO ([link to study here]). In these cases, treating the SIBO often leads to a significant reduction or resolution of IBS symptoms.

So, could some IBS cases be misdiagnosed as SIBO? Many studies show that IBS symptoms improve or even resolve when treated for SIBO. One review paper discussed Rifaximin, an antibiotic used to treat SIBO, as a potential treatment for IBS. In another study focused on children, 66% of kids diagnosed with IBS had SIBO, and treating the SIBO resolved their IBS symptoms.

Despite these findings, the relationship between IBS and SIBO is still debated in the medical community.

Effective Treatment Requires Addressing the Root Cause

Treatment won’t be effective unless the underlying cause is addressed first. For instance, if SIBO is caused by celiac disease, it won’t improve without following a strict gluten-free diet. Once the underlying issue is managed, the treatment approach can then be tailored, whether through traditional or integrative methods.

Traditional doctors treat SIBO with antibiotics

Antibiotics are the primary treatment for SIBO. They’re often used alongside motility agents to help move food and bacteria through the intestines, preventing bacteria from building up.

In more severe cases, elemental diets may be recommended. These are liquid diets where all nutrients are already broken down and don’t need to be digested. Because the nutrients are absorbed so quickly, bacteria don’t have time to act on them and cause symptoms. This approach is typically short-term and is designed to “starve” the bacteria.

Integrative and Holistic Approaches to Treating SIBO

As mentioned earlier, addressing the underlying cause is essential for effective treatment. Once that’s done, integrative and holistic physicians may use the following therapies to help manage SIBO:

• Herbal antibiotics (such as garlic, oregano, berberine, or combinations)
• Probiotics (with or without)
• Vitamins
• Diet and nutritional interventions
• Motility agents
• Digestive enzymes
• Acupuncture
• Elimination diets
• Hypnotherapy
• Relaxation techniques
• Stress reduction strategies
• Addressing sleep disorders
• Elemental diets
• Antibiotics

Many different diets are used to manage SIBO.

Which diet is used depends on the clinical scenario and the practitioner.

Most of the diets have the same goal of reducing sugars that the bacteria would consume.

• A general low sugar/carb diet is preferred if symptoms can be controlled.
• Other diets used are:
• Low FODMAP
• SCD- Specific Carbohydrate Diet
• GAPS- Gut and Psychology Syndrome Diet
• Candida diet
• Paleo-The Paleolithic Diet
• Ketogenic diet
• A ” SIBO Diet” is often a combination of the low FODMAP diet and the SCD diet, but this strict of a dietary regiment is not always needed. A handout of the diet can be found here.
• Cedars Sinai low fermentation diet

Managing SIBO Symptoms Long-Term

The long-term outcome of SIBO can vary; unfortunately, recurrence is common. Symptoms often return or worsen during the holidays, typically due to increased stress and eating more sugar, carbohydrates, or alcohol. These can trigger symptom flare-ups.

While a return of symptoms and relapse can be frustrating, several strategies may help prevent or delay the return of SIBO symptoms:

• Eat a clean diet: Focus on a primarily plant-based, whole-food diet. See my related article on the best diet for SIBO.
• Minimize processed foods and sugar: Bacteria thrive on sugar, so cutting back can help reduce symptoms.
• Reduce stress: Chronic stress negatively impacts gut health, so find ways to manage stress.
• Exercise regularly: Physical activity supports gut health and encourages beneficial gut bacteria.
• Prioritize sleep: Getting enough rest is crucial for overall health and gut function.

Some people may follow a less restrictive version of one of these diets for long-term management. Remember, each person’s needs differ, so find what works best for you.

Action Plan If You Suffer From SIBO Symptoms

• Talk to your physician: If you suspect you have symptoms of SIBO, discuss the possibility with your doctor.
• Identify underlying causes: Work with your doctor to pinpoint the root cause of your symptoms for the best outcome.
• Make dietary and lifestyle changes: While waiting for your evaluation, consider making dietary adjustments, improving sleep, managing stress, and focusing on overall wellness to help reduce symptoms.
• Advocate for yourself: Don’t give up—many practitioners may not be familiar with SIBO. Bring printed research papers to help educate them.
• Be proactive: Stay positive and take charge of your health—you can feel better!

• Overview of SIBO
• How to test and treat SIBO
• Testing for SIBO– a consensus paper