Sulfapyridine is primarily used as an antibacterial agent, particularly in the treatment of certain bacterial infections. It is effective against a range of gram-positive and gram-negative bacteria, making it useful in managing conditions like pneumonia, urinary tract infections, and skin infections. Additionally, it has been employed in the treatment of dermatitis herpetiformis, a chronic skin condition associated with celiac disease, due to its anti-inflammatory properties. In veterinary medicine, sulfapyridine is sometimes used to treat infections in animals. Its mechanism of action involves inhibiting the synthesis of folic acid in bacteria, thereby preventing their growth and replication. However, its use has declined with the advent of newer antibiotics with fewer side effects.