Inclusion criteria:
Signed informed consent form.
Diagnosis of Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) based on medical history and valid diagnostic documentation, including imaging findings, previous liver biopsy reports, or other medical records confirming the diagnosis.
Stable clinical condition, including Child-Pugh class A or B with a score of 8 or less and without failure of vital organs.
Presence of Fibrosis-4 Index (FIB-4) or Liver Stiffness Measurement (LSM) within a range indicative of monitorable liver fibrosis.
No systemic antibiotic or probiotic use within 4 weeks prior to screening.
Age between 18 and 75 years old.
Exclusion criteria:
Clinically active hepatic encephalopathy, grade II or higher, or a history of hospitalization due to hepatic encephalopathy within the past three months.
Active hepatocellular carcinoma (HCC) or other active malignancies.
Current use of rifaximin or medications with clinically significant interactions with rifaximin..
A known history of hypersensitivity or allergy to rifaximin or any of its components.
Severe renal impairment, including an estimated glomerular filtration rate (eGFR) of less than 30 mL/min/1.73 m² or requiring dialysis.
Pregnancy or breastfeeding: Women of childbearing potential must have a negative pregnancy test and agree to use a reliable method of contraception throughout the study.
Concurrent participation in another interventional study or use of any medication or treatment that could significantly affect the study outcomes, such as statins or similar therapies, depending on the study protocol.
Presence of serious comorbid conditions that would make participation in the study impossible or unsafe, such as unstable cardiac disease, active systemic infection, or other severe clinical conditions.
Inability to comply with the study instructions or inability to attend the study visits and follow-up assessments