Since September 1994, danaparoid (Orgaran), a heparinoid, has been used in our centre to treat patients with thrombocytopenia occurring during heparin therapy and who need continuing antithrombotic therapy. We carried out a retrospective study using clinical and biological data on the first 13 consecutive patients treated with danaparoid (for 1 to 18 consecutive days). The platelet count returned to normal for ten patients, but one patient died having contracted a severe sepsis and bleeding occurred in one patient with acute renal failure. In the three other cases, the diagnosis of heparin induced thrombocytopenia (HIT) was in retrospect unlikely and the death of these patients was related to severe underlying diseases which were held responsible for thrombocytopenia. We confirm that danaparoid appears to be an effective, well-tolerated substitute for heparin in HIT patients. The French regulation Temporary Authorization for Prescribing Medicines allowed the prompt use of this as yet unmarketed drug and collection of reliable and pertinent data.