Bloody nipple discharge is a clue in the detection of ductal carcinoma of the breast that do not display a mass. Since sensitivity of discharge cytology is not sufficiently high and mammary ductendoscopy (MS) contributes to the diagnosis of intraductal lesions. We set out to determine whether the intraductal approach is effective for detection of ductal carcinoma. We performed 445 MS procedure in 323 patients who had nipple discharge but no overt mass. The diagnostic accuracy rates of discharge cytology and intraductal breast biopsy (IDBB) were studied in detecting malignancy. The therapeutic value of IDBB for intraductal papillomas was studied in 73 patients. Out of 323 patients, 80 had breast cancer and 155 had intraductal papilloma. MS detected intraductal tumors in 47 cases (58.8%). IDBB was performed in 35 of these 47 cases. The sensitivity was 37.1% by touch cytology, 68.6% by IDBB, and 82.8% by directed ductal lavage cytology. Of the 73 intraductal papilloma patients who were followed for more than 3 years, the therapeutic effectiveness of IDBB was recognized in 57 (78.1%). Directed ductal lavage cytology was the most sensitive method in detecting malignancy. MS and IDBB were benefit in the treatment of intraductal papilloma.