An amino acid based polymer, oligomer or copolymer containing at least 5 mol % of units of a basic amino acid selected from the group consisting of lysine, argenine, ortnithine, trgptophane and mixtures thereof and at least about 5 mol % of a polymerizable compound selected from the group consisting of aliphatic or cycloaliphatic amines, alicyclic amines, diamines, triamines, tetraamines, aliphatic amino alcohols or mixtures thereof, an a process for the production of the said polymer, oligomer or copolymer by condensing at a temperature of at least 120.degree. C. said basic amino acid with at least one of said polymerizable compounds.