With the extensive use of Hickman catheters in patients requiring cytotoxic chemotherapy there is now a resurgence of Gram-positive septicaemia among these patients during the neutropenic periods. We are currently running a prospective randomized study of prophylactic teicoplanin during insertion of Hickman catheters to determine if it reduces the incidence of Gram-positive septicaemia. A total of 44 patients have completed the study (23 in the teicoplanin group and 21 in the control group). The diagnoses were: acute myelogenous leukaemia (13), non-Hodgkin's lymphoma (16), Hodgkin's disease (11), chronic granulocytic leukaemia (3) and acute lymphoblastic leukaemia (1). The number of days between insertion of Hickman catheters and the development of neutropenia was: teicoplanin group: mean 14.7, median 11, range 0-53; control group: mean 11.8, median 10, range 0-37. In the treated patients, there were four episodes of line-associated Gram-positive septicaemia and a total of four organisms were isolated. In the control group, 10 organisms were isolated from a total of nine episodes of line-associated Gram-positive septicaemia. The organisms were: coagulase-negative staphylococci (8), Streptococcus B, (1), Strep. faecalis (1), Strep. mitis (1), alpha streptococcus (1), diphtheriods (1) and Staphylococcus aureus (1). All organisms were sensitive to teicoplanin. No adverse reaction was observed in any patient. Prophylactic teicoplanin during insertion of Hickman catheters may therefore reduce the incidence of line-associated Gram-positive septicaemia in neutropenic patients.