Process for the preparation of products of the reaction of polyaspartimides and amino acids by reaction of amino acids with polyaspartimides in aqueous medium at pH values at which at least 5% of the amino groups in the amino acids are in non-protonated form in equilibrium with the protonated form, and use of the reaction products obtainable in this way and of products of the reaction of polyaspartimides with alkanolamines or aminated C.sub.1 -C.sub.30 -fatty alcohol alkoxylates which contain as copolymerized units up to 50 mol % of ethylene oxide and/or propylene oxide per mol of fatty alcohol, as additive to detergents and cleaners, as scale inhibitor and as dispersant.