A fluorescence diagnosis system has a viewing system at least one light source and a camera system. The at least one light source can be operated in three modes, a first generating white light, a second with a first fluorescence excitation light of a first excitation wavelength and a third in which a second fluorescence excitation light of a second excitation wavelength is generated producing a fluorescence image in the NIR range. The camera system is sensitive at least in the visible and the NIR range. The system further comprises an image processing system for converting the fluorescence image in the NIR range into a visible image.