Deutsch: Laktation / Français: Lactation / Italiano: Lattazione 

Lactation refers to the secretion of milk from the mammary glands, and the period of time that a mother lactates to feed its young. This process can occur with almost all post-partum female mammals, although it may have predated the existence of mammals. The process may also be referred to as breastfeeding or nursing when referring to humans.

For most species, the milk comes out of the mother's nipples. However, the platypus releases milk through ducts in its abdomen. For one species of mammal, the Dayak fruit bat, it is instead the male that normally produces milk.

Some newborn infants may produce neonatal milk (or witch's milk), though this is considered to be a normal physiological occurrence, and is therefore untested and untreated.

Galactorrhea is a term for milk production unrelated to childbirth or nursing. It can occur in males and females of different mammal species, and may be caused by hormonal imbalances and/or unusual psychological stimuli.