Emulsion comprising at least one amphoteric chelating agent comprising a complex based on aluminum and ethylenediaminetetraacetic acid or its trisodium salt having the general formula [Al (Y) Bn] c'Dc with B representing OH-, BO2-, H + , Y representing a tetracarboxylate which may be protonated four times to form ethylenediaminetetraacetic acid, n representing an integer equal to 0, 1, 2 or 3, where D is a counterion, preferably Na +, c being an integer equal to 0.1 , 2 or 3 and where c 'is a relative number that has the same absolute value as c； characterized in that said amphoteric chelating agent is stabilized by an amino acid chosen from the group comprising glycine, histidine, arginine, lysine, phenylalanine, alanine, isoleucine, leucine, methionine, proline , valine, tryptophan, serine, glutamine, cystine and mixtures thereof, for use to protect the skin against aggressive chemical agents, said emulsion being applied at least 5 minutes, preferably at least 10 minutes and even more preferably at at least 15 minutes before contact with said aggressive chemical agent.Emulsión que comprende al menos un agente quelante anfótero que comprende un complejo a base de aluminio y de ácido etilendiaminotetraacético o su sal trisódica que presenta la fórmula general [Al(Y)Bn]c'Dc con B representando OH-, BO2-, H+, representando Y un tetracarboxilato que puede estar protonado cuatro veces para formar el ácido etilendiaminotetraacético, representando n un número entero igual a 0, 1, 2 o 3, siendo D un contraión, preferiblemente Na+, siendo c un número entero igual a 0, 1, 2 o 3 y siendo c' un número relativo que tiene el mismo valor absoluto que c； caracterizada por el hecho de que dicho agente quelante anfótero es estabilizado mediante un aminoácido elegido entre el grupo que comprende la glicina, la histidina, la arginina, la lisina, la fenilalanina, la alanina, la isoleucina, la leucina, la metionina, la prolina, la valina, el triptófano, la serina, la glutamina, la cisti
