According to current knowledge, Osler's disease may be caused by gene defects of several distinct genes, causing vascular fragility and lack of contractility. The most typical symptoms are recurrent spontaneous nose bleedings. Other target organs of the disease include skin, lungs, intestinal tract, brain and liver, but symptoms in these organs are less common. The diagnosis is based on clinical findings, family history and can, if necessary, be confirmed by a gene test. Osler's disease is treated symptomatically. There is no curative treatment.