Abstract: Whether menopausal hormone therapy (MHT) increases the risk of breast cancer has been controversial. In September 2019, the famous medical journal, the Lancet, published a meta-analysis that has gathered the worldwide evidence of MHT and incidence of breast cancer, showing that in addition to vaginal estrogen, all type of MHTs increased the risk of breast cancer, and the risk increased steadily with the duration of MHT use. The risk was greater for oestrogen-progestagen therapy; the excess risk persisted after the drug was stopped for more than 10 years. Low doses of MHT or natural progesterone do not prevent the risk of breast cancer. This article interprets the meta-analysis and emphasizes that MHT should be taken into account of increasing the risk of breast cancer, and the risks and benefits should be fully evaluated.