Theoretically calcium and iron can be taken together, and if the two nutrients are taken together they will not affect the patient, and their absorption will not affect each other. However, in clinical practice, patients are generally advised to take them separately, and it is advisable to take calcium supplements at night before sleep and iron supplements after meals to promote better absorption and utilization of the above nutrients. If the patient forgets to take the two together at the right time, it will not have any particular effect. For patients who need to supplement these nutrients, it is important to avoid the effects of food while taking the relevant medication, for example, patients should not drink strong tea, coffee or alcoholic beverages.