Premarin is a combination of artificial estrogen hormones, which supplement estrogen produced by the ovaries. Premarin is used to treat conditions stemming from menopause, as the female body cannot produce enough estrogen. Premarin should be taken for the shortest possible time to relieve menopausal symptoms since estrogens can increase the risk of many serious conditions.Premarin is a female hormone used to reduce the intensity of symptoms associated with menopause such as dryness of the vagina and hot flashes. Premarin may also be used to treat osteoporosis in postmenopausal individuals. At times, Premarin is used alongside other medicines to treat cancer in men and women. Premarin can be used to replace estrogen in those diagnosed with ovarian failure or other diseases that can result from lack of estrogen in the body. Premarin works by helping the body make more estrogen. If you are using Premarin to treat symptoms around the vagina, consult your doctor about the safety of other products applied directly inside the vagina.