Serotonin receptor (5HT3) inhibition by ondansetron (Motavallian-Naeini et al., 2012[35]), granisetron (Fakhfouri et al., 2010[7]), tropisetron (Motavallian et al., 2013[34]) or ramosetron (Min and Rhee, 2015[30]) has beneficial property on experimental colitis in rat. This evidence concerns the gene HTR3A and colitis.