Sulfanilamide is a synthetic sulfanilamide compound primarily known as the first sulfonamide antibiotic, used as an antibacterial agent against infections caused by streptococcal and other bacteria. It inhibits bacterial growth by interfering with folic acid synthesis. Historically, it has been effective in treating urinary tract infections, meningitis, and other bacterial infections in humans and veterinary applications for livestock and pets. It also served as a key intermediate in the development of modern sulfonamide drugs. In laboratory settings, high-purity sulfanilamide (>99.9%) is used as a reagent for diazotization titration, particularly in analytical chemistry for the determination of nitrites via the Griess reaction or similar methods.