The fluorescent dye indocyanine green (ICG) has been used in medicine for many years. More recently, it has also been used to study human lymphoedema and the superficial lymphatic system. ICG lymphography is called “Near-Infrared Fluorescence Lymphatic Imaging” (NIRFLI). It should be noted that ICG is an off-label application in NIRFLI. However, a “milestone” study in 2011 was conclusive, with over 4000 NIRFLI procedures performed in the study of primary and secondary lymphoedema, as well as on healthy volunteers and human cadavers.