Rixmin® 400 contains rifaximin, a rifamycin-derived antibiotic with broad-spectrum activity against Gram-positive and Gram-negative bacteria. Unlike many systemic antibiotics, rifaximin is minimally absorbed from the gastrointestinal tract, allowing it to act primarily within the intestines while maintaining a low risk of systemic side effects.

The medication is widely used for the management of traveler's diarrhea caused by non-invasive strains of Escherichia coli, reduction of recurrent episodes of hepatic encephalopathy, and treatment of irritable bowel syndrome with diarrhea (IBS-D). It is also frequently utilized in the management of small intestinal bacterial overgrowth (SIBO) under physician supervision.

Rifaximin works by inhibiting bacterial RNA synthesis, reducing bacterial growth and helping restore intestinal microbial balance. Treatment decisions, dosing schedules, and duration of therapy should always be determined by a qualified healthcare professional.