When iron supplementation is given to patients clinically, polysaccharide iron complex is usually chosen as a way to supplement iron, which is associated with adverse reactions such as gastrointestinal irritation or constipation, which are some adverse reactions of the gastrointestinal tract. Some patients may have darker and darker stools after taking iron supplements. Patients are advised to take iron supplements orally under the guidance of a doctor to replenish the iron in the body. In addition, patients will be advised that iron supplementation is best taken at the same time as vitamin C, because vitamin C can promote the absorption of iron.