During hyperthyroidism, patients are required to take medication to treat it. It is important to determine whether it is okay to breastfeed based on the medication currently being used. Because drugs have certain toxicity, if they are more toxic, or if they are given in larger doses at one time, they can easily affect the baby through breast milk, so safer drugs should be chosen. Clinically, breastfeeding mothers with hyperthyroidism can take methimazole and propylthiouracil in divided doses, which can treat the mother’s hyperthyroidism and reduce the effect of peak drug concentration on the baby, which is safe for both the mother and the baby. In addition, it takes time to metabolize the medication, so it is recommended that mothers with hyperthyroidism take the medication after breastfeeding rather than before breastfeeding, and try to interval about 3-4h after taking the medication before the next breastfeeding, consult your doctor for the exact time. The length of the interval should be decided according to her metabolic condition and the dose of the medication to reduce the possibility of the baby being affected by the medication. If the mother’s condition is serious and the need for medication is high, it is recommended not to breastfeed first, and the infant can be fed with age-appropriate formula.