According to the present invention there is provided a process for retarding the discolouration of dicarboxylic acids, said process comprising heating said dicarboxylic acid to a temperature above its melting point and adding at least one metal ion sequesterant to said dicarboxylic acid. A further aspect of the present invention provides a composition comprising at least one dicarboxylic acid and at least one metal ion sequesterant. A further aspect of the present invention provides for the use of metal ion sequesterants to retard the discolouration of dicarboxylic acids, particularly molten dicarboxylic acids.