Forty-three patients received home parenteral nutrition (HPN) for 4 to 13 months (median, 30 months) with a total treatment period of 153 patient-years. All patients had central venous catheters; 71 PVC subclavian catheters, 138 Broviac catheters, and 16 other catheters were used. Broviac catheters were introduced into the central veins via a tunnel on the chest (94 catheters) or on the thigh (44 catheters). Eighty-two episodes of catheter septicaemia occurred in 28 (65%) of the patients, corresponding to an incidence of catheter septicaemia of 1 in 1.9 patient-years. The commonest microorganisms grown from the blood were coagulase-negative staphylococci, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Candida species. Septicaemia incidence was 1 in 2.6 catheter-years with the Broviac catheter on the chest and 1 in 1.6 catheter-years with the Broviac catheter on the thigh. In 49 cases the patient was treated with both antibiotics and change of the catheters, in 26 cases with antibiotics alone, and in 5 cases with change of the catheter alone. The antibiotic therapy was given for 3 to 15 days (median, 7 days). No patient died of catheter septicaemia. The relapse rate was low (less than 10%) and did not differ significantly between the three treatment groups. It is concluded that catheter septicaemia is a common complication of HPN. In most cases it runs a mild course. Bacteriaemia can often be eradicated by a brief antibiotic therapy without catheter exchange.