We describe the case of a cafe waiter aged 38, with an extensive sub-malleolar left internal varicose ulcer, which was chronic and very painful. This ulcer had been developing for 17 years and had not cicatrized for two years, which meant professional invalidity despite repeated attempts at therapy (qualified local care in a special department, hospitalizations, stripping, and filament graft). In the absence of any arterial, deep venous or lymphatic affection, deep biological disturbances meant this ulcer was classed in the category of hypercoagulable ulcers. A heparin treatment transformed the local situation and made it possible for a complementary surgical graft. Vascular ulcers resistant to properly administered local, vascular and general treatments, should lead us to investigate the possibility of hypercoagulability, whose best parameter is the high index of potential thrombodynamic (I.P.T.) calculated according to the thromboelastogram on the total blood. These hypercoagulable ulcers can be cured with a prolonged heparin treatment, in doses sufficient to normalize the I.P.T. without having to investigate true hypercoagulability with the T.C.K. It seems to us that this treatment is most effectively carried out in hospital, where it is possible to achieve constant heparinization by electric syringe and reequilibration of the biological constants.