Used primarily as an antibacterial agent, especially in the treatment of urinary tract infections. It works by inhibiting bacterial growth through interference with folic acid synthesis, which is essential for DNA and protein production in bacteria. Due to its sulfonamide structure, it may be effective against a range of gram-positive and gram-negative organisms. However, its use has declined over time due to the availability of more effective and safer antibiotics. It may also be used in combination with other drugs to enhance antimicrobial activity. Not commonly used today due to higher risk of adverse effects compared to modern alternatives.