Iron supplements make stools black because iron combines with hydrogen sulfide in the gastrointestinal tract, causing iron sulfide to turn stools black. In our daily life, we have experienced that after eating iron-rich food, blood tofu, the stool will become black, and if we stop using iron supplements, the stool will become normal color. If there is no combination of gastrointestinal symptoms, such as abdominal pain, acid reflux, heartburn, and vomiting of coffee-colored liquids, and no intestinal bleeding, there is no need for special treatment. Since iron supplements are mainly used in the prevention and treatment of iron deficiency anemia, it is recommended to take them during or after meals to reduce the stimulation of the stomach. Various iron supplements should not be taken with strong tea to prevent affecting the efficacy. It is important to note that daily iron supplements should be used in preventive doses, and should not be used in therapeutic doses for too long. Under the guidance of a doctor, it is important to help choose the right type of medication and to help evaluate the efficacy and safety of iron supplements.