Clostridium difficile infection is caused by ingestion of C. difficile spores after antibiotic use disrupts normal gut flora. It most commonly causes diarrhea in a hospital setting and can progress to pseudomembranous colitis. Treatment involves discontinuing antibiotics, rehydration, and administration of oral vancomycin or metronidazole. Recurrence is common after initial treatment and may require prolonged or multi-drug therapy. Severe complications include toxic megacolon and sepsis.