Aromatase inhibitors are a class of drugs that block the enzyme aromatase, which is responsible for the conversion of androgens into estrogens in the body. By inhibiting this enzyme, aromatase inhibitors reduce the levels of estrogen in the body, which can be beneficial in the treatment of hormone receptor-positive breast cancer. Aromatase inhibitors are commonly used in postmenopausal women with breast cancer to prevent the growth and spread of the cancer cells. These drugs may also be used in the treatment of other conditions such as endometriosis and infertility.