Conjugated estrogen is an active pharmaceutical ingredient that contains a mixture of steroidal and non-steroidal components that are obtained from pregnant mares' urine. Conjugated estrogen is used as an external source and is prescribed as a replacement of female natural hormones. Estrogen has many well-known effects on the tissues of the body. It causes the growth of the inner lining of uterus, secretion of cervix, development & growth of female sexual organs and maintains the sexual characteristics of females, such as hair growth of underarm and pubic area and countering of body and bone. Menopause is diagnosed when a woman has not had menses for one year. Due to the low production of estrogen in the body, about 85% of women have symptoms such as hot flushes, bone loss, vaginal dryness and shrinkage of tissues. For these symptoms, menopause hormone treatment therapy is the most effective treatment. Conjugated estrogen helps menopausal women treat symptoms such as shrinkage of vaginal tissue, vaginal dryness, hot flashes, bone loss and painful intercourse. However, there are many side effects of conjugated estrogen such as breast swelling, abdominal pain, vaginal bleeding, nausea and mood swings. Patients with heart & kidney diseases should be careful while taking conjugated estrogen as it cause retention of salt & water in the body. Also, a high dose of conjugated estrogen can cause clotting of blood in legs and lungs. Hence, smokers have a high risk of clots and are recommended to quit smoking if they are prescribed conjugated estrogen. Before taking conjugated estrogen, its side effects, dosage, drug interactions, risks and storage should be reviewed properly.