It has been reported that supplements with Akkermansia muciniphila (Gu et al., 2021), deletion of ghrelin (Tuchaai et al., 2022), palmatine (Zhang et al., 2018) and polysaccharides derived from Shenling Baizhu San (Lv et al., 2022) could ameliorate colitis, mainly by suppressing tryptophan metabolism. Here, GHRL is linked to colitis.