Von Willebrand disease: The most common inherited bleeding disorder, in which a clotting protein called von Willebrand factor is deficient or defective. Von Willebrand factor is made by cells lining the wall of blood vessels. Several types of von Willebrand disease have been described. All types affect both males and females. Symptoms can include easy bruising, nosebleeds, bleeding from the gums after a dental procedure, heavy menstrual bleeding in women, blood in the stool and urine, and excessive bleeding after a cut or other accident or after surgery. Von Willebrand disease is usually mild and often does not require treatment. Treatment may be needed only after surgery, a tooth extraction, or an accident. For those who need treatment, medications such as desamino-8-arginine vasopressin (DDAVP) can be given to raise the levels of von Willebrand factor, which reduces the tendency toward bleeding. Antihemophilic factor (Alphanate) may be given to decrease bleeding in patients with the disease who must have surgery or other invasive procedures. Blood plasma or certain factor VIII preparations may also be used to decrease bleeding.