There is no limit to the maximum time of intravenous iron injection, it needs to be judged according to the patient’s condition and tolerance, the weekly medication is usually 2~3 times, after the condition is relieved, it can no longer be injected, some patients may need to be infused for 4 weeks. Intravenous iron has low molecular iron dextrose, high molecular iron dextrose, sodium iron gluconate, iron sucrose, etc. It is mainly used for patients who need intravenous iron treatment because of poor effect of oral iron, usually 2~3 times per week, and the time of stopping the intravenous injection needs to be judged according to the patient’s condition, and the condition is relieved, it can be switched to oral iron for treatment. Clinically, this may be about 4 weeks in some patients. The use of intravenous iron needs to be under the guidance of medical professionals. Common adverse reactions include hypotension, fever, chills, nausea, etc. It is contraindicated in the treatment of patients with non-iron deficiency anemia, iron overdose, or iron utilization disorders.