Sulfanilamide is primarily used as an antibacterial agent, particularly in the treatment of infections caused by susceptible strains of bacteria. It is effective against a variety of bacterial infections, including those of the urinary tract, respiratory system, and skin. The compound works by inhibiting dihydropteroate synthase, thereby blocking folic acid synthesis essential for bacterial growth and multiplication, making it a valuable tool in both human and veterinary medicine.

In addition to its medical applications, sulfanilamide is also used in research settings to study bacterial resistance mechanisms and the efficacy of antimicrobial agents. Its role in the development of sulfa drugs has been pivotal in the history of antibiotics, paving the way for the creation of more advanced and targeted treatments.

Furthermore, sulfanilamide has found use in the synthesis of other chemical compounds, including dyes and other pharmaceuticals. Its versatility and effectiveness continue to make it a significant compound in both clinical and industrial contexts.