Serotonin has a multifunctional role in many different organs serving either as a neurotransmitter in the central nervous system or a paracrine factor in the gastrointestinal tract. Over 90% of serotonin is synthesised in the enterochromaffin cells of the intestine and subsequently taken up by platelets. The involvement of platelet-derived serotonin in liver mass restoration after partial hepatectomy or toxic injury has been greatly investigated during the last decade. There is a growing body of evidence implicating serotonin in hepatic regeneration through altered expression of serotonin receptor subtypes in the liver. This review article provides a brief overview on the current knowledge about the actions of serotonin in liver regeneration.