Successful treatment of infection in patients with neutropenia is usually possible if several principles are followed. The most important of these is prompt administration of antibiotic therapy, even if the patient has no symptoms or signs of infection other than fever. Most infections are caused by gram-negative bacilli, but even "nonpathogenic" organisms can cause serious infections. Antibiotic combinations should be selected that provide broad-spectrum coverage and are active against the most prevalent organisms in the hospital. Aminoglycosides are often ineffective in patients with persistent neutropenia and should not be used alone. A variety of effective combination regimens are available for initial therapy of presumed or proved infection in patients with neutropenia, including a beta-lactam plus an aminoglycoside or two beta-lactam antibiotics.