A method for determining skin allergenicity, the method comprising: causing a reaction between an organic compound that has at least one thiol group or amino group and emits fluorescence, and a mixture containing two or more test substances, wherein the organic compound is N-(arylalkylcarbonyl)cysteine or α-N-(arylalkylcarbonyl)lysine, and the organic compound is an organic compound that emits fluorescence at 200 to 400 nm, and has a molar absorption coefficient at a maximal absorption wavelength of 10 L/mol·cm or more and 500000 L/mol·cm or less; determining an amount of the organic compound after the reaction or an amount of a product of the reaction by an optical measurement using a fluorescence detector, wherein, in the optical measurement using the fluorescence detector, an excitation wavelength is 200 to 350 nm, and a fluorescence wavelength is 200 to 400 nm; subj ecting, to chromatography treatment, a reaction product of the step of causing the reaction between the organic compound and the mixture, calculating, by a formula below, a depletion percent of the organic compound from an average value of peak areas of the organic compound determined by the optical measurement using the fluorescence detector, Depletion percent (% depletion) of organic compound that has at least one thiol group and emits fluorescence = [1 - (Average value of peak areas of post-reaction unreacted organic compound that has at least one thiol group and emits fluorescence/Average value of peak areas of blank-test organic compound that has at least one thiol group and emits fluorescence)] × 100; or Depletion percent (% depletion) of organic compound that has at least one aminol group and emits fluorescence = [1 - (Average value of peak areas of post-reaction unreacted organic compound that has at least one thiol group and emits fluorescence/Average value of peak areas of blank-test organic compound that has at least one amino group and emits fluorescence)] × 100. causing a reaction between an organic compound that has at least one thiol group or amino group and emits fluorescence, and a mixture containing two or more test substances, wherein the organic compound is N-(arylalkylcarbonyl)cysteine or α-N-(arylalkylcarbonyl)lysine, and the organic compound is an organic compound that emits fluorescence at 200 to 400 nm, and has a molar absorption coefficient at a maximal absorption wavelength of 10 L/mol·cm or more and 500000 L/mol·cm or less; determining an amount of the organic compound after the reaction or an amount of a product of the reaction by an optical measurement using a fluorescence detector, wherein, in the optical measurement using the fluorescence detector, an excitation wavelength is 200 to 350 nm, and a fluorescence wavelength is 200 to 400 nm; subj ecting, to chromatography treatment, a reaction product of the step of causing the reaction between the organic compound and the mixture, calculating, by a formula below, a depletion percent of the organic compound from an average value of peak areas of the organic compound determined by the optical measurement using the fluorescence detector, Depletion percent (% depletion) of organic compound that has at least one thiol group and emits fluorescence = [1 - (Average value of peak areas of post-reaction unreacted organic compound that has at least one thiol group and emits fluorescence/Average value of peak areas of blank-test organic compound that has at least one thiol group and emits fluorescence)] × 100; or Depletion percent (% depletion) of organic compound that has at least one aminol group and emits fluorescence = [1 - (Average value of peak areas of post-reaction unreacted organic compound that has at least one thiol group and emits fluorescence/Average value of peak areas of blank-test organic compound that has at least one amino group and emits fluorescence)] × 100.