BACKGROUND Menorrhagia (heavy menstrual bleeding) is a benign yet debilitating social and health condition. Treatments prescribed in order to reduce excessive menstrual blood loss include prostaglandin synthetase inhibitors, antifibrinolytics, the oral contraceptive pill and other hormones. The combined oral contraceptive pill (OCP) is claimed to have a variety of beneficial, inducing a regular shedding of a thinner endometrium and inhibiting ovulation thus having the effect of treating menorrhagia and providing contraception. OBJECTIVE To determine the effectiveness of oral contraceptive pills compared with other medical therapies, placebo or no therapy in the treatment of heavy menstrual bleeding. METHODS We searched the Menstrual Disorders and Subfertility Group trials register (search dates: Oct 1996, May 2002, June 2004, April 2006 and June 2009) for all publications which describe randomised trials of OCP for the treatment of menorrhagia. This register is based on regular searches of MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, the hand searching of 20 relevant journals and conference proceedings, and searches of several key grey literature sources. METHODS All randomised controlled comparisons of OCP versus other medical therapies, placebo or no treatment for the treatment of menorrhagia. Women of reproductive years with regular heavy periods, measured either objectively or subjectively and greater than, or equal to, two months follow up. METHODS All assessments of trial quality and data extraction were performed unblinded by at least two reviewers. Only one trial of 45 women met the inclusion criteria and none were excluded. RESULTS As the trial used a cross-over design, only data from the first treatment period (cycles three and four) were analysed. The results from all the three mefenamic acid groups were combined. There was no significant difference in menstrual blood loss (MBL) between those women treated with the OCP and danazol, mefenamic acid or naproxen. CONCLUSIONS One small study found no significant difference between groups treated with OCP, mefenamic acid, low dose danazol or naproxen. Overall, the evidence from the one study is not sufficient to adequately assess the effectiveness of OCP.This review was unable to achieve its stated objectives because of the paucity of the data.