Abstract:Gut microbiota plays an essential role in intestinal homeostasis and brain health.Serotonin is an important monoamine neurotransmitter in the brain.More than 90% of serotonin is converted from tryptophan metabolism in colonic enterochromaffin cells and exerts system-wide regulations.Recent studies have demonstrated that the effects of serotonin may be affected by gut microbiota.Specific microbes in the gut have the ability to produce serotonin.The gut microbiota and its metabolites,such as butyric acid,can regulate the level of serotonin by affecting the activity of tryptophan hydoxylase or the metabolism of tryptophan.In turn,serotonin and serotonin reuptake inhibitors can modulate the composition and function of gut microbiota.The gut microbiota-serotonin interaction is of great significance to the host health,and the mechanism underlying the interaction remains to be elucidated.This article reviews the research progress on gut microbiota,serotonin,and their interaction,aiming to provide references for in-depth investigation on how the gut microbiota-serotonin interaction regulates gut and brain health.