Oxytocin is a peptide hormone secreted from the posterior pituitary. Its best-known function is to increase milk secretion in breastfeeding women. It can be used pharmacologically to induce uterine contractions and sustain labour. However, it is thought that its contribution to birth is minimal at physiologically normal blood levels. This hormone, which acts as a neurotransmitter in the central nervous system, is also effective in regulating blood circulation. It balances the mood and is important in regulating behaviour in different emotional states. It helps to experience positive emotions. It has anti-inflammatory properties and this feature also increases the healing speed of wounds on the body. It reduces stress by lowering cortisol levels. It increases the pain threshold. It enables socialisation and prevents falling into an introverted mood. It increases sexual arousal and it makes it easier to empathize. Oxytocin is no longer the simple “love hormone” and, like many other hormones, has complex interactions with human health and behaviour. Although good progress has been made, much more research is needed to understand the effects of oxytocin fully.