Is used for: Generic Xifaxan is an antibiotic that fights bacterial infection only in the intestines. Generic Xifaxan is used to treat travelers' diarrhea caused by E. coli in adults and children who are at least 12 years old. Most people get this infection by eating food or drinking fluids that have been contaminated with the bacteria. Generic Xifaxan is also used to lower the risk of worsened brain function, or hepatic encephalopathy, in adults with liver failure. Brain function can be affected when the liver stops working and cannot remove toxic substances from the body.