Evidence of mast cell implication in IBS pathophysiology is also supported by studies identifying an improvement in gut symptoms after administration of the stabiliser disodium chromoglycate [24,161,162] or ketotifen, a histamine H1-receptor antagonist and mast cell stabiliser, which led to reduced visceral perception, particularly in hypersensitive IBS patients [163]. This evidence concerns the gene HRH1 and irritable bowel syndrome.