Rifagut 400 mg is an antibiotic tablet containing rifaximin, used to treat bacterial infections in the intestines. It is commonly prescribed for infectious traveler's diarrhea, irritable bowel syndrome with diarrhea (IBS-D), and to prevent and manage hepatic encephalopathy caused by liver disease. The medicine works by killing harmful bacteria in the gut, reducing toxin production, and improving bowel and liver health. It is taken orally, with or without food, as prescribed by a doctor. Common side effects include nausea, headache, dizziness, and abdominal discomfort.