The invention concerns the use if isothiocyanate of general formula (I): R1—N═C═S wherein: R1 represents an alkyl, alkenyl, alkynyl, aryl, acetyl, alkylcarbonyl, alkoxy, cycloalkyl, aryloxy, arylcarbonyl group, carboxylic acid or a —(CH2)nR3 group wherein n represents an integer ranging between 1 and 5 and R3 represents a polar functional group, advantageously a halogen atom, a sulphoxide, carbonyl, nitro, thioester, thioether, sulphonyl, sulphinyl, nitrile group, carboxylic acid, carboxylic ester, alkylthio or hydroxyl, a thiocyanate of general formula (II): R2—S═C═N wherein: R2 represents an alkyl, alkenyl, alkynyl, aryl, acctyl, alkylcarbonyl, alkoxy, cycloalkyl, aryloxy, arylcarbonyl group, carboxylic acid, carboxylic ester or a —(CH2)nR3 group, wherein n represents an integer ranging between 1 and 5 and R3 represents a polar functional group, advantageously a halogen atom, a sulphoxide, carbonyl, nitro, thioester, thioether, sulphonyl, sulphinyl, nitrile group, carboxylic acid, carboxylic ester, alkylthio or hydroxyl, or mixtures thereof for making a medicine or a cosmetic composition for inhibiting tyrosinase.