To study cell electroporation, entrance into or efflux out of the cell of fluorescent dyes is often studied. However, when a cell suspension is exposed to high-voltage electric pulses, various electrochemical reactions occur at each electrode-solution interface. One of these reactions is the oxidation of the metal ions of the electrode. As a result of this, metal ions are released from the anode into the solution.In this study, influence of iron ions released from the stainless-steel anode on the fluorescence of the fluorescent molecules was studied. Calcein, which is used in studying cell electroporation, as well as anticancer drugs porphyrin-sulphonate and adriamycin, which can be used in combined application of the electroporation and photodynamic tumor therapy, were used.Iron ions suppressed the intensity of fluorescence of adriamycin, porphyrin-sulphonate, and calcein in solution. In the presence of 2.5 mM Fe3+, fluorescence of porphyrin sulphonate was suppressed by 100%, and adriamycin - by 50%. When mouse hematoma MH-22A cells preloaded with calcein were treated by a square-wave electric pulse with the duration of 2 ms and the amplitude of 1.6 kV/cm, a decrease in the number of fluorescent cells was observed: after the incubation for 5 min only 50% of cells were still fluorescent. However, when the cell suspension was supplemented with 0.55 mM FeCl3, quick decrease in the number of fluorescent cells was observed. When 5 min had passed after an electric pulse (2 min after the addition of Fe3+ ions), the fraction of fluorescent cells was only 25%.Therefore, the iron ions released from the stainless-steel anode can quench the fluorescence of the molecules not only in the solution but inside electroporated cells as well.