An intact vascular system is crucial for the function and maintenance of a healthy human body. Angiologists are highly specialised physicians who deal extensively with the diseases of the blood vessels (arteries, veins, arterioles, venules, capillaries) and lymphatic vessels. Diseases of the blood and lymphatic vessels are very complex. Therefore angiologists work closely with phlebologists and vascular surgeons together thus providing an optimal interdisciplinary treatment. Particularly in the treatment of varicose veins angiologists have achieved great successes with modern therapeutic concepts (e.g. minimal-invasive sclerotherapy of varicose veins with microwaves).