The course of oral iron therapy takes about 4-6 months. The specific treatment time for supplemental iron deficiency anemia is as follows: 1. For iron deficiency anemia with clear diagnosis, oral iron therapy is usually given, such as application of ferrous succinate , ferrous sulfate, ferrous fumarate, etc. Usually after 5-10 days of oral iron, the reticulocytes in the peripheral blood of the patient will rise, and after 2 weeks of oral iron, the hemoglobin will rise, and after 1-2 months of oral iron, the hemoglobin will reach the normal level; 2. For more serious anemia, it may take 2-3 months for the hemoglobin to reach the normal level, but after the hemoglobin is normal, the patient should continue to take iron for 2-3 months to replenish the body indicator of stored iron, and after the serum ferritin also returns to normal, the drug can be stopped. It is a mistake for more patients to stop taking the drug after the hemoglobin is normal. This is because sudden discontinuation of the drug may result in the indicators of iron stores in the body not being fully replenished, and after discontinuation of the drug, the symptoms of anemia may easily appear again in a short period of time, requiring repeated treatment, which may have adverse effects on the body. Therefore, for patients with iron deficiency anemia, they need to be psychologically prepared to take the drug for 4-6 months. If patients have obvious gastrointestinal reactions, such as stomach discomfort, nausea and vomiting, after taking iron orally, they should replace the iron promptly and choose to take iron treatment that is less stimulating to the gastrointestinal reactions, so that patients can insist on taking iron for a long time.