Efficacy of Rifaximin in Patients With Small Intestinal Bacterial Overgrowth Presenting With Abdominal Bloating.

Healthy Group Inclusion Criteria: 1. Age between 18 and 70 years, both genders included. 2. No special gastrointestinal discomfort such as bloating or abdominal pain, regular bowel movements, and normal stool characteristics. 3. Negative hydrogen/methane breath test. Exclusion Criteria: 1. Pregnant or lactating women. 2. History of gastrointestinal malignancy or gastrointestinal surgery. 3. Past diagnosis or suspicion of lactose intolerance. 4. Confirmed extra-digestive system diseases such as urinary system (chronic kidney disease, etc.), immune system (scleroderma, etc.), nervous system (Parkinson's, etc.), endocrine system (diabetes, etc.). 5. Abnormalities in professional anxiety and depression symptom rating scales. 6. Use of antibiotics, probiotics within two weeks, endoscopic examination, or use of prokinetics, secretagogues, antifoaming agents, antispasmodics, opioids, antidepressants within one week. 7. Those who cannot or are unwilling to sign an informed consent form. Patient Group: Inclusion Criteria: 1. Age between 18 and 70 years, both genders included. 2. Chief complaints of abdominal bloating and/or distension; outpatients with abdominal bloating and/or distension more prominent than other symptoms. 3. Positive hydrogen/methane breath test. Exclusion Criteria: 1. Pregnant or lactating women. 2. History of gastrointestinal malignancy or gastrointestinal surgery. 3. Past diagnosis or suspicion of lactose intolerance. 4. Confirmed extra-digestive system diseases such as urinary system (chronic kidney disease, etc.), immune system (scleroderma, etc.), nervous system (Parkinson's, etc.), endocrine system (diabetes, etc.). 5. Moderate to severe abnormalities in professional anxiety and depression symptom rating scales. 6. Use of antibiotics, probiotics within two weeks, endoscopic examination, or use of prokinetics, secretagogues, antifoaming agents, antispasmodics, opioids, antidepressants within one week. 7. Those who cannot or are unwilling to sign an informed consent form.