Heparin induced thrombocytopenia and thrombosis is a rare but serious
adverse effect. The first report was published in 1958. At the present
time, the Vidal Dictionary contains ''warning'' about heparin thrombo
cytopenia and thrombosis. The development of knowledge about this subj
ect in the international papers is reported. The role of the French Sy
stem of Health, and the problem of analysis in Pharmacovigilance are r
elated in details.