A reduction in the number of neutrophil LEUCOCYTES per cubic millimetre of circulating blood to below 1,500 per mm³ is generally accepted as constituting neutropenia. Several infective diseases are characterised by neutropenia, including typhoid fever (see ENTERIC FEVER), INFLUENZA and MEASLES. It is commonly induced by the cytotoxic drugs used to treat cancers. The term febrile neutropenia is used when a patient receiving such medication, so by definition immunosuppressed, (see IMMUNOSUPPRESSION) develops a raised temperature. Because of the risk that the fever represents bacterial infection that may lead to SEPTICAEMIA, it is usual to start treatment with high-dose intravenous antibiotics without waiting for bacteriological confirmation.