Based on amino acid sequence similarities that exist between the fibrinogen gamma-chain and kappa-casein, and also functional similarities between milk and blood coagulation, considerable effort has been made to investigate the effects of milk proteins and peptides on platelet function and thrombosis. In particular, a number of peptides derived from the glycomacropeptide segment of kappa-casein, have been shown to inhibit platelet aggregation and thrombosis. KRDS, a peptide from lactoferrin has also been shown to inhibit platelet aggregation but to a lesser extent than its fibrinogen analogue RGDS. Despite their functional and structural similarities they do not act in the same way on platelet function and are thought to affect thrombus formation differently. Further investigation is needed to determine if these milk-derived bioactive peptides are released naturally following ingestion and might therefore be useful as the basis for milk-based products with anti-thrombotic properties.