Nitrofurantoin, (Furadantin, or N-(5-nitro-2-furfurylidene)-l-amino-hydantoin), is an antibiotic agent that fights bacteria in the body. Nitrofurantoin is a yellow, crystal-line compound of bitter taste, which darkens on exposure to light or alkali. This antibiotic is commonly used to treat urinary tract infections. It is also extensively used in prophylaxis of uncomplicated lower urinary-tract infections. Nitrofurantoin has been used since 1950s and it is a well-known and studied drug with limited antibiotic resistance.