[2][5] The discharge can be milky, clear, green, purulent, bloody, or faintly yellow.

[5][6] Nipple discharge may be normal, such as milk in late pregnancy or after childbirth, and in newborns during the first weeks of life.

[2][5] The discharge can be milky, clear, green, purulent, bloody, or faintly yellow.

[5][6] Nipple discharge can arise from any one or more of the 15 to 20 milk ducts that each breast contains, and its causes can be divided into normal (physiological) and abnormal (pathological).

[2][5] Milky liquid from nipples is normal during the last few weeks of pregnancy, after childbirth and during breastfeeding.

[2][5] Some newborn babies may leak a milky liquid which is usually normal and lasts a couple of weeks.

[5] Spontaneous nipple discharge unrelated to pregnancy or lactation is considered abnormal, but mostly have a non-serious cause.

[10] Up to half of women with intraductal papillomas may present with bloody nipple discharge, but it can also be straw-coloured.

[5] Some condition that cause a raised prolactin can result in a milky liquid appearing from nipples.

[1][9] However, guidance on investigations varies and tests are more likely performed if the discharge is bloody, from one breast, and the woman is age over 50.

Treatment will depend on the cause found, and may involve changing medication, having a lump removed, applying a cream to treat a skin condition or being given medication to treat the condition causing the discharge.

If the person wishes to conserve the ability to breastfeed and only single-duct discharge is present, then ductoscopy or galactography should be considered in view of performing a localised duct excision.