Abstract: External grooving on a catheter traps microorganisms nurtured by mucus in a patient's body. The grooving also traps contaminating debris, originating outside the body, that migrates into the body along the catheter exterior. Energy, which may be a propagating vibration or electrical energy or a radioactive material, is carried to the groove (or grooves), from a source outside the body. This function is performed by a fiber embedded or held in the catheter, or by a liquid column (e.g., in an annular lumen) in the catheter, or in other ways. The energy disables microorganisms and disintegrates debris trapped at the groove. The groove depth, interface geometry, and in the case of vibrational energy the vibration frequency too, are selected to minimize projection of energy into the patient's tissues. Suction may be applied as through an auxiliary lumen (or, in some drain catheters, intermittently through the primary drain lumen itself), to remove resulting detritus at the grooving.