Protein C (PTC) is a Vitamin K dependant factor which, after activation by Thrombin, acts with it's co-factor Protein S to degrade the activated forms of Factors V and VIII. Inherited PTC deficiency accounts for 5-7% of recurrent thrombo-embolic episodes in young adults. Deficiency can be the result of a defect at the substrate binding site (qualitative, Type II deficiency) or as a result of reduced levels of otherwise normal PTC (quantitative, Type I deficiency). Most cases are heterozygous, but some homozygous cases have been described in neonates with massive visceral thrombosis and purpura fulminans. Acquired PTC deficiency can be found in Vitamin K deficiency, oral anticoagulation therapy, liver disease, DIC and in the early post-operative phase.