Hydrogen sulfide SIBO , commonly called hydrogen sulfide (H2S) SIBO, or intestinal sulfide overproduction (ISO) occurs when excessive hydrogen sulfide gas is produced in the gut due to an overgrowth of bacteria. This form of SIBO commonly causes diarrhea, abdominal pain, bloating, and particularly foul-smelling gas like sulfur or “rotten eggs”. Dr. Elena Ivanina uses specialized testing to understand if H2S SIBO is driving your symptoms.
What is Hydrogen sulfide (H2s) SIBO?
ISO is characterized by excess hydrogen sulfide (H2S) gas produced in the intestines, primarily by sulfate-reducing bacteria. Symptoms can include diarrhea, bloating, abdominal pain, fatigue and brain fog. For decades, SIBO breath testing focused on measuring two primary gases: hydrogen and methane. There was no breath test available to measure excess hydrogen sulfide, so ISO could not be detected – until just recently. Although many doctors have not yet started testing for ISO, it is standard testing in Dr. Ivanina’s practice.
Symptoms:
- Diarrhea or loose stools
- Urgency with bowel movements
- Abdominal bloating or distension
- Abdominal pain or cramping
- Excessive or foul-smelling gas
- Gas with a “rotten egg” odor
- Nausea
- Discomfort after eating
- Changes in bowel habits
- Food sensitivities or intolerances
- Fatigue
- Brain fog
Why does Hydrogen sulfide (H2s) SIBO happen?
Your gut microbiome contains organisms that produce and consume different gases as they metabolize nutrients. Hydrogen sulfide is naturally present in the gut. Normally, your digestive system maintains a balanced microbial environment. When bacterial populations, intestinal motility, anatomy, or other protective mechanisms become disrupted due to various root causes such as infections, excessive hydrogen sulfide production can occur in the gut and contribute to symptoms.
Meet Dr. Elena Ivanina, Hydrogen sulfide (H2S) SIBO specialist
Dr. Elena Ivanina is a triple board-certified integrative gastroenterologist specializing in SIBO and complex digestive disorders offering beyond the usual traditional approach and incorporating holistic and functional medicine. As the founder of Gut Love, she brings together gastroenterology with functional medicine, nutrition, microbiome medicine and diagnostics. For hydrogen sulfide SIBO, Dr. Ivanina looks beyond elevated gas levels to investigate why your intestinal environment allowed the imbalance to develop, and then creates a personalized strategy that addresses both the overgrowth and its underlying root cause to prevent recurrence.
Hydrogen sulfide SIBO FAQs
How is hydrogen sulfide SIBO diagnosed?
Hydrogen sulfide SIBO requires testing capable of measuring hydrogen sulfide in addition to hydrogen and methane. A three-gas breath test can measure these gases after you consume a test substrate. Dr. Ivanina may also use your medical history and additional diagnostic testing to investigate factors contributing to the overgrowth.
How is hydrogen sulfide SIBO treated?
Treatment is individualized based on your symptoms, test results, medical history, and suspected root causes. Your plan may include antimicrobial treatment, targeted nutritional changes, and strategies to support intestinal motility and a healthier microbial environment. Dr. Ivanina considers the entire digestive system rather than focusing exclusively on lowering hydrogen sulfide levels. The goal is to help you maintain a healthier gut in the long term.
Is hydrogen sulfide SIBO different from hydrogen SIBO?
Yes. Hydrogen SIBO is characterized by excessive hydrogen production in the small intestine from bacterial fermentation, whereas hydrogen sulfide SIBO involves excessive hydrogen sulfide production anywhere in the gut. The two can produce overlapping symptoms, but hydrogen sulfide is associated with diarrhea and foul or rotten-egg-smelling gas. Measuring multiple gases can provide a clearer picture of what is happening in your gut.
Learn More with the Heal SIBO Program
Created by Dr. Elena Ivanina, DO, an integrative holistic board-certified gastroenterologist and SIBO specialist, the Heal SIBO Program gives you a clear, root-cause framework for understanding SIBO, from symptoms and lab tests to treatment options and recurrence prevention.
The program includes a 35-minute educational video with Dr. Ivanina, a SIBO Root-Cause Evaluation Framework, a Symptoms & Signs Guide, and an educational guide to herbal antimicrobials—everything you need to become a more informed participant in your own healing journey and have a more productive conversation with your healthcare provider.
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