Dysfunctional uterine bleeding results from disruption of the normal sequence of ovarian cyclic hormonal stimulation of the uterine endometrium. Treatment of dysfunctional uterine bleeding previously consisted of surgical or hormonal manipulation, or both. The present study was conducted on 34 patients in a randomized double-blind fashion to evaluate the efficacy of treating dysfunctional uterine bleeding with intravenous Premarin. Bleeding stopped in 72% of patients who received intravenous Premarin and in 38% who received placebo (P=.021). Premarin was effective in terminating endometrial bleeding in patients with biopsyproved pathology consisting of secretory, proliferative, menstrual, polypoid, or cystic hyperplasia, as well as endometritis.