4 ms·Gut bacteria manufacture 95% of body's serotonin4 points by alexjray 8y agoDrScump 8y ago(September 2012) Actual title: "That Gut Feeling". It's about a lot more than serotonin.sudoaza 8y agoAwesome, gut biota is turning out to be a major player mostly ignored. We should trial drugs/chemicals by this bacterias to see their effect on them.