There is no fastest way to replenish iron, children can eat more animal offal, green leafy vegetables to replenish iron, you can also take iron supplements such as ferrous succinate to replenish iron. 1. Animal offal: some animal offal such as pork liver, lean meat and so on contain more iron, which can provide raw materials for children’s blood production. 2. Green leafy vegetables: some green leafy vegetables, such as spinach, which is also rich in iron, children can eat some spinach to supplement iron. 3. Iron supplements: Supplementation with iron supplements, such as ferrous succinate, is the most effective way to supplement iron, which can correct anemia in children. Taking ferrous succinate may cause nausea, vomiting and other gastrointestinal adverse reactions, and need to be used under the guidance of a doctor. When children are iron deficient, it is recommended that they seek medical attention in a timely manner and take reasonable and standardized iron supplements under the guidance of a doctor.