Laser is light that does not exist in nature. It is monochrome, brighter than the sun and can be dosed very well. Laser therapies today are established standards in many medical fields. Specialized centers combine the expertise of medical specialists with sophisticated technology. There is not "one laser", but many. Laser procedures are used for diagnostics and therapy, from photodynamic therapy (PDT) to thermal procedures and laser surgery. Laser medicine offers treatment options for congenital vascular tumors and malformations (e.g. port-wine stains and haemangiomas), urogenital and proctological diseases, tumor diseases (brain tumors, white skin cancer) and respiratory diseases. Many benign skin diseases may also be treated with light or laser. In rare diseases such as Osler–Weber–Rendu disease (HHT), neurofibromatosis type I or tuberous sclerosis, laser allows a more gentle treatment, sometimes the only treatment at all. The procedures are usually less invasive and can already be applied to children and elderly patients, often on an outpatient basis.