Excess serotonin in the gut can activate T-cells to proliferate, leading to hyperactive immune responses associated with colitis, inflammatory bowel disease, and other gut issues.

“too much serotonin in the gut also activates te- cells to proliferate and it's associated with um hyperactive immune response in the gut associated with colitis and inflammatory bowel disease and other gut issues so too much serotonin in the gut is is uh involved in inflammation in the gut”