Mechanism of action, antimicrobial spectrum, pharmacology, adverse reactions and therapeutic uses of nitrofurantoin, a broad-spectrum antimicrobial agent, are discussed. The frequency and potential severity of reactions attributed to nitrofurantoin, plus its inability to achieve therapeutic blood concentrations, relegate this drug to a position of secondary importance. Nitrofurantoin compares favorably with other standard agents for the therapy of acute and recurrent urinary tract infections in women which may be caused by susceptible organisms, and it is an effective chemoprophylactic agent for patients with recurrent urinary tract infections. The compound has no apparent adverse effects on the developing fetus and can be used in pregnant women. This is not sanctioned by the package insert, however. Nitrofurantoin should not be administered when the possibility of bacteremia exists, as the drug does not achieve therapeutic serum levels when administered orally. Nitrofurantoin is contraindicated for patients with renal insufficiency. The value of this compound for men with acute urinary tract infection, recurrent urinary tract infection, acute bacterial prostatitis or chronic bacterial prostatitis has not been established. There are no indications for prescribing parenteral nitrofurantoin.