‘If you prick us, do we not bleed?’

William Shakespeare and many others recognized the connection between trauma and bleeding, and the association of bleeding with childbirth is well established. However, even though the associations are well known, the understanding of the mechanisms underlying blood clotting is relatively recent. Bleeding and clotting continue to be major causes of mortality and morbidity. Cerebrovascular accidents and myocardial infarction, together with cancer, continue to be the main causes of death worldwide. In spite of advances in the understanding of the mechanisms of haemostasis and thrombosis in health and disease, there is still much to learn and a lot more to do to reduce the incidence of bleeding and clotting.