We carried out an open, uncontrolled, prospective study to evaluate intraluminal antibiotic therapy for bloodstream infections arising from subcutaneously tunneled central venous catheters in patients receiving parenteral nutrition therapy at home. Seven bacterial infections were treated with intraluminal antibiotics (mean duration, 8.6 days) sometimes accompanied by systemic antibiotics (mean duration, 2.1 days). All seven infections were cured. Two infections caused by Candida species were treated with intraluminal amphotericin B. Fungal infections was suppressed during treatment but later relapsed, as confirmed by pulsed field DNA electrophoresis typing of bloodstream isolates. The concentration of antibiotic was assayed in intraluminal fluid from catheters of patients receiving treatment with vancomycin or gentamicin. The concentration was initially approximately 5 mg/mL, and it remained at > or = 2.5 mg/mL throughout the period that the solution was locked in the catheter. Our findings show that intraluminal therapy is effective against selected bacterial infections and can suppress fungal infections in subcutaneously tunneled catheters.