Abdominal bloating is a common clinical symptom in the digestive system, with obscure origins and complex mechanisms. Its etiology can be attributed to organic diseases and various Functional Gastrointestinal Disorders (FGIDs). In recent years, the roles of Small Intestinal Bacterial Overgrowth (SIBO), Oral-Cecal Transit Time (OCTT), and gut microbiota dysbiosis in Functional Abdominal Bloating/Distention (FAB/D) have garnered increasing attention. Currently, there is a lack of diagnostic tests and effective treatment measures for patients with bloating. The hydrogen/methane breath test is a safe, economical, and non-invasive examination recommended for diagnosing SIBO. Rifaximin, an antibiotic that acts exclusively in the intestines, has been widely validated for its efficacy in SIBO and in patients with SIBO co-occurring with Irritable Bowel Syndrome (IBS). However, research on the role of SIBO in the production of bloating symptoms and the extent to which rifaximin treatment of SIBO alleviates symptoms in clinical bloating patients is still lacking. This study aims to investigate the efficacy of rifaximin in patients with SIBO who primarily present with bloating. Exploring clinical treatment options for bloating provides a reference for its management. Furthermore, questionnaires on psychiatric symptoms and fecal microbiota analysis for patients with bloating-type SIBO can help clarify the etiology of bloating, offering a basis for the etiological treatment of bloating patients in the next steps.

The study enrolled subjects who primarily complained of abdominal bloating, and underwent breath testing, along with healthy volunteers. Study participants were required to meet the inclusion criteria, not meet the exclusion criteria, and sign an informed consent form. After enrollment, they completed a case report form. Basic demographic information of the study participants, results of routine laboratory tests, clinical characteristics related to symptoms, results and values of breath test, and other data were recorded. Patients were required to provide stool samples and conduct psychiatric questionnaire scoring, and the healthy control group was also required to provide stool samples. After enrollment, patients took rifaximin dry suspension at a dosage of 0.4 g twice a day for two weeks, recording medication intake and adverse reactions through a diary card during the medication period. Two weeks after the end of the medication, the diary cards and medication packaging were collected, and the case report forms were supplemented. Stool samples were taken again, and anxiety and depression scale scores were recorded to document changes in clinical symptoms. One month after the end of the medication, patients were required to undergo a repeat breath test, and follow-ups for changes in abdominal bloating symptoms were conducted three and six months after the end of the medication .

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.