The invention relates to a device for making visible a pathological change in a part of a patient's body labeled with a fluorescent dye, the device having: a first selectable light source (11, 17), which emits light in the excitation wavelength range of the fluorescent dye, in order to trigger the emission of light in the emission wavelength range of the fluorescent dye, a second selectable light source, which emits visible light outside the emission wavelength of the fluorescent dye, and a means for selectively switching the first and the second light source on and off.