A prospective evaluation of the haemostatic mechanism was undertaken in 15 normal primigravidas and in 12 primigravidas with mild to moderately severe pre-eclampsia in order to further examine the possibility that disseminated intravascular coagulation may occur in this clinical syndrome. The only coagulation abnormality demonstrated was a prolongation of bleeding time. The data do not support the suggestion that significant disseminated intravascular coagulation is associated with pre-eclampsia. The addition of the heparinoid drug sodium pentosan polysulphate to the therapeutic regimen resulted in a significant fall in platelet factor 3 availability and in decreased aggregation against ADP but conferred no objective clinical improvement. We conclude that the drug has no place in the management of established pre-eclampsia.