Easy bruising and bleeding are not only characteristic manifestations of clotting and platelet disorders, they are also prominent features in some heritable collagen disorders, such as the Ehlers-Danlos syndromes (EDS). The EDS comprise a heterogeneous group of connective tissue diseases sharing clinical manifestations in skin, ligaments and joints, blood vessels and internal organs. Most EDS subtypes are caused by mutations in genes encoding the fibrillar collagens type I, III and V, or in genes coding for enzymes involved in the post-translational modification of these collagens. Easy bruising is, to a variable degree, present in all subtypes of EDS, and is because of fragility of the capillaries and the perivascular connective tissues. Vascular fragility affecting medium-sized and large arteries and veins is typically observed in the vascular subtype of EDS, caused by a molecular defect in collagen type III, an important constituent of blood vessel walls and hollow organs. Extensive bruising, spontaneous arterial rupture, leading to severe internal bleeding or premature death, and rupture of hollow organs, such as the intestine or the gravid uterus are predominant features of this subtype. Haematological studies including evaluation of clotting factors, platelet aggregation and bleeding time are usually normal in patients with EDS, except for the Hess test (Rumple-Leede test), which may be abnormal, indicating capillary fragility. In some forms of EDS confirmation of the clinical diagnosis and subtype is possible with biochemical and molecular studies.