The number of days of continuous calcium supplementation at one time should not be generalized, depending on the degree of calcium deficiency and the patient’s ability to absorb calcium. In the case of calcium supplementation for infants, the infant’s body needs to be tested for calcium deficiency and calcium supplementation should be targeted. If given only as a preventive measure, calcium supplementation should generally not be given for more than 14 consecutive days and can be given at 14-day intervals. If a calcium deficiency exists, a trace element re-test can be performed after 30 days of continuous calcium supplementation. If adults are deficient in calcium for a long time, it will easily lead to osteoporosis and require long-term calcium supplementation, but one continuous calcium supplementation should not exceed 30 days, and the specific duration of calcium supplementation varies from person to person. For pregnant women, calcium supplementation usually takes about 3 months, and it is recommended to consult a professional doctor for the specific duration and dosage of calcium supplementation. During the calcium supplementation period, patients should be careful not to eat with some vegetables containing oxalate, carbonate and phosphate, and to supplement vitamin D at the same time, which can help the absorption of calcium.