The Authors describe an extremely rare fatal case (sixth case in the literature) of anaphylactic shock following a fluorescein angiography. This is the first report in which the diagnosis of anaphylactic reaction to the dye was made through laboratory analyses. The diagnosis of fatal shock due to sodium fluorescein was made based on clinical, laboratory and immunohistochemical data. Mast-cell tryptase was dosed in serum and a pulmonary immunohistochemical evaluation was performed. Tryptase, a neutral protease of human mast-cells is a potentially important indicator of mast-cell involvement in anaphylactic events.