We report on a 3 1/2 year old girl with purpura fulminans after varicella who made a complete recovery on treatment with an appropriate high-dose heparin regimen and other supporting measures. Several attempts to reduce the heparin dosage from the initial high level (85 IU/kg/hour) to the usual level (25 IU/kg/hour) were followed each time by an immediate deterioration in the clinical condition.