oxytocin
Oxytocin is a hormone that is produced in the brain when you are happy or when you are relaxed. It is often called the "cuddle hormone" because it is responsible for making you feel happy and content.
When she saw the baby, she started to produce a lot of oxytocin.
The drug is designed to increase the level of oxytocin in the brain, which is supposed to make you feel happy and relaxed.