Xifaxan is a prescription medication that contains the active ingredient rifaximin. It is primarily used to treat certain gastrointestinal conditions, including traveler's diarrhea caused by non-invasive strains of E. coli and irritable bowel syndrome with diarrhea (IBS-D). This antibiotic works by inhibiting the growth of bacteria in the intestines, helping to alleviate symptoms such as abdominal pain and diarrhea. Xifaxan is usually taken orally in tablet form and is considered effective with a low risk of developing antibiotic resistance. Always consult a healthcare professional for proper diagnosis and treatment options.