In all, 88 patients with haematological malignancies requiring Hickman catheters for intensive chemotherapy were randomized to receive either one single bolus intravenous injection of teicoplanin, 400 mg, or no teicoplanin immediately before insertion of a double-lumen Hickman catheter. Lower incidences of catheter-related Gram-positive sepsis were recorded in patients receiving prophylactic teicoplanin; exit site infection, tunnel infection and catheter-related Gram-positive septicaemia were all reduced. The benefit of prophylactic teicoplanin was observed particularly among patients who were already neutropenic at the time of catheterization. All Gram-positive organisms isolated from infected skin sites or from blood cultures taken from Hickman catheters were susceptible to teicoplanin. No adverse reaction was reported in any of the patients receiving prophylaxis. Prophylactic teicoplanin, therefore, may be used routinely for patients requiring insertion of Hickman catheters for intensive chemotherapy, to reduce the early incidence of catheter-related sepsis, particularly during the period of neutropenia following chemotherapy.