Pharmacopoeia General 13 categories of drugs to be avoided during lactation: 1. Hormonal drugs: resist growth and hinder the formation of hormones in the body. 2, anti-tumor drugs: once a week application of methotrexate is acceptable in breastfeeding women, but the infant’s blood parameters should be closely followed. 3, thyroid function agents: taking such drugs can lead to infants with low thyroid function. 4.Bromide: rash and drowsiness. 5.Isoniazid: dizziness, insomnia, and inattention can cause isoniazid poisoning as well as central nervous excitement in infants. 6.Potassium preparations: can cause infants’ body temperature to drop. 7.Methotrexate: damages the kidneys of infants, and can come out with nausea and vomiting. 8.Chloramphenicol: accumulation poisoning, resist infant bone marrow. 9, ergometrine preparations: because it has the effect of inhibiting the activity of prolactin, reducing the secretion of milk. 10, iodine and iodine-containing preparations: because iodine can lead to goiter and hypothyroidism in infants, while avoiding exposure of infants to excessive radioactive activity. 11, antibiotics: some antibiotics during breastfeeding can cause allergic reactions in infants and lead to the occurrence of drug-resistant strains. 12, contraceptives: oral contraceptives during breastfeeding can resist the secretion of milk, overdose can affect the baby’s genitals, but also greatly reduce the absorption of minerals and proteins in breast milk. 13, other types of drugs: lithium preparations, central nervous system drugs (such as antidepressants, psychosuppressants, etc.), certain drugs that cause adverse reactions in infants due to individual differences should be properly avoided or closely monitored. In addition, lactating mothers drink alcohol, smoking and drug addiction are detrimental to the infant: maternal alcohol consumption not only reduces lactation and inhibits the infant, but also has a negative impact on the infant’s neurological development smoking has a higher incidence of respiratory infections and may expose the infant to carcinogenic substances.