Ciprofloxacin is an antibiotic used for infectious diarrhea caused by certain bacteria such as enterotoxigenic E. coli, Shigella, Campylobacter, and Salmonella Typhi, and is also approved for typhoid fever and complicated abdominal infections (when combined with metronidazole). It can be effective for traveler’s diarrhea and shigellosis, especially when started early, as it shortens the duration and severity of symptoms. However, its use is limited by rising antibiotic resistance and safety concerns like tendon injury, aortic tears, and risk of C. difficile infection. In areas with high resistance, particularly South and Southeast Asia, azithromycin is preferred, and ciprofloxacin should never be used for Shiga toxin–producing E. coli. The usual adult dose is 500 mg twice daily for 5–7 days for diarrhea, or 10 days for typhoid fever, with use best guided by resistance patterns and illness severity.