Tranexamic acid reduces bleeding by inhibiting the breakdown of blood clots. It is cost-effective and heat-stable with a long shelf life. In the WOMAN trial, tranexamic acid reduced deaths due to bleeding with no increase in thromboembolic events. The effect was greatest when women received tranexamic acid within 3 h of childbirth (RR = 0.69, 95% CI 0.52-0.91). The WHO recommends that women with post-partum haemorrhage receive 1 g tranexamic acid intravenously as soon as possible after giving birth, followed by a second dose if bleeding continues after 30 min or restarts within 24 h since the first dose. Urgent treatment is critical because women with post-partum haemorrhage bleed to death quickly, and tranexamic acid is most effective when given early. Evidence suggests there is no benefit when the drug is given more than 3 h after bleeding onset. Alternative routes of administration and use of tranexamic acid in the prevention of post-partum haemorrhage are research priorities.