While its exact appetite-stimulating mechanisms are unclear, it is purported to exert an analgesic and antiemetic effect through the antagonism of central 5HT2/5HT3 receptors and has recently been shown to increase ghrelin levels in a non-cancer setting and improve caloric intake and gastric motility in patients with cancer-related anorexia [60,61,62]. This evidence concerns the gene GHRL and Anorexia.