Dacryography is the only means of exploring the permeability of the lacrymal ducts and to conclude as the whether watering of the eyes is organic or functional. Pre-operatively, it is indispensable in order to orientate the surgical intervention, it is definitely indicated if there is a relapse of watering of the eyes. The appearance of new surgical techniques, such as the use of venous or arterial grafts, has given rise to a new interest in this technique, which up to now had been considered as an exceptional investigation.