A hormone that is responsible for stimulating the contractions of the uterine preceding birth: Oxytocin has the additional function of accelerating the lactation process of the mother and also serves a role in bonding.

1. A hormone produced by the hypothalamus that is stored and released by the pituitary gland; pitocin: Oxytacin causes contractions of the uterus and the release of milk from the mammary glands.

Oxytocin is a smooth muscle contraction-stimulating hormone found in the neurohypophysis.

The hormone oxytocin is made in the brain and plays a role in childbirth and lactation by causing muscles to contract in the uterus (womb) and the mammary glands in the breast. Animal studies have shown that oxytocin also plays a role in pair bonding, mate-guarding, and social memory.

Oxytocin is related to another hormone called vasopressin.
2. In pharmacy, a synthetic form of the hormone that is important in childbirth: Oxytocin is obtained from beef and hog pituitary glands, or especially by synthesis, and used chiefly in obstetrics to induce labor and to control postnatal hemorrhage.
3. Nasally administered hormone: Oxytocin has played a role in generating trust in humans.

In a 2005 study, it was shown that in a risky investment game, experimental subjects given oxytocin displayed what the researchers deemed "the highest level of trust" twice as often as the control group who were given placebos.

The same experiment with the subjects who were told that they were interacting with a computer showed no such reaction, leading to the conclusion that oxytocin was not merely affecting risk-aversion.

4. A hormone with various anti-stress functions: Oxytocin is noted to reduce blood pressure and cortisol levels in addition. to increasing tolerance to pain and reducing anxiety.

Oxytocin may play a role in encouraging "tend and befriend", as opposed to a "fight or flight", behavior in response to stress.