Nalidixic acid is primarily used as an antibacterial agent, particularly effective against gram-negative bacteria. It is commonly applied in the treatment of urinary tract infections caused by susceptible organisms. The compound works by inhibiting bacterial DNA synthesis, which prevents the bacteria from multiplying and spreading. In veterinary medicine, nalidixic acid is also utilized to treat bacterial infections in animals, ensuring their health and well-being. Additionally, it serves as a research tool in microbiological studies to understand bacterial resistance mechanisms and to develop new antibacterial strategies.