A native, chromatographically purified 1-AT preparation having a purity of at least 0.7 PU/mg protein and a relative plasma 1-AT activity of at least 120% is disclosed. The ratio of active to inactive 1-AT is higher than in plasma. Furthermore, a method of producing this preparation is disclosed, as well as the use of a carrier material, e.g. an inorganic carrier material such as hydroxylapatite for separating active 1-AT from inactive 1-AT.