A few years ago, scientists discovered the existence of a second brain in our body. There are 200 million neurons in our belly! Researchers are just beginning to decrypt the permanent secret dialogue between these two brains. Their discovery has opened great hopes for new therapies. Some brain disorders, such as Parkinson, could trace their origins in our belly and start by attacking our intestine’s neurons. Even more astonishingly, our second brain contains a spectacular colony of hundred thousand billions bacteria whose activity has an impact on our personality, our choices, our shyness or, on the contrary, our recklessness. This discovery of a new intelligence in our belly makes researchers beginning to admit that our brain is not quite the only one being in command.