The case of a patient with von Willebrand's syndrome successfully treated with Lyndiol® (one tablet per day) is presented. The patient's AHG level was increased from 0.5 per cent to 24 per cent during eight months of therapy. A temporary decrease in bleeding time occurred without any accompanying increase in Factor VIII at the beginning of treatment. Platelet adhesivity could not be corrected. No major side effects of the drug have been observed other than moderate gynecomastia and marked growth acceleration.