Ikarashi et al. confirmed that an increase in the expression level of Aquaporin 3 (AQP 3) is involved in the onset of morphine‐induced constipation, while an increased intracellular Mg2+ concentration can weaken this effect and promote the water inflow of intestinal mucosal epithelial cells into the intestinal cavity, which is conducive to defecation.29 This evidence concerns the gene AQP3 and constipation disorder.