Have you ever watched a baby nurse? It’s amazing to watch a cranky, tense, hungry infant instantly slip into a relaxed, sleepy, almost drunken state. 

We sometimes attribute this familiar scene to the beauty of the mother-baby bond. 

But, the truth is, in a benign and loving way, mother’s milk really does deliver a mild drug-like compound to the baby. 

Drug-like compounds in milk? It’s true. Think about it this way: if a baby, a calf, or any other mammal didn’t want to nurse, the survival of the species would be in trouble. So, nature devised these compounds to reward babies for nursing.