A monofilament polypropylene guiding suture was inserted into a secreting duct in 72 female patients (aged 15-78 years) with nipple discharge. Cannulation and injection of contrast material was successful in all patients before galactography and of methylene blue dye before excision. Patients did not report discomfort, no injuries ensued, and no duct was perforated. This technique should expedite excision of a discharging duct and any lobules.