Sulfanilamide is primarily used as an antibacterial agent, particularly in topical treatments for skin infections, burns, and wound care. It works by inhibiting bacterial growth through interference with folic acid synthesis, which is essential for bacteria to reproduce. It has been widely used in creams and ointments to prevent infection in second- and third-degree burns. Though largely replaced by newer antibiotics for systemic use, sulfanilamide remains effective in localized treatments due to its ability to act directly at the site of infection with minimal systemic absorption. It is also used in some veterinary applications and as an intermediate in the synthesis of other sulfonamide drugs.