Clinicians can now offer their patients the first nonsystemic, gastrointestinal selective antibiotic to receive FDA approval. The agency recently approved rifaximin (Xifaxan, Salix Pharmaceuticals) tablets for the treatment of TD caused by noninvasive strains of Escherichia coli in those 12 years of age or older. Rifaximin is currently approved for use in 17 countries worldwide. It is expected to be available in U.S. pharmacies in August.