 Postpartum haemorrhage PPH remains a leading cause of maternal mortality, despite treatment with conventional methods. Uncontrolled reports and three small randomised controlled trials have suggested that misoprostol may have an additive effect to routine treatment, and there is a serious danger that this method will be used widely without research to document the effectiveness or risks of this method. In this randomised controlled trial RCT, we propose to test whether 600 μg of sublingually administered misoprostol in women requiring additional uterotonics after delivery, and after routine syntocinon to all women during or after delivery, has additional effects above the additional conventional uterotonics in reducing PPH. Women with measured blood loss greater than or equal to 500 mls in 4 Karachi hospitals who give consent will be given locally routine treatment for PPH. In addition, they will be enrolled by drawing the next of a series of randomised treatment packs containing misoprostol or placebo. The primary outcome measure will be blood loss greater than or equal to 500 mls after enrolment. 