A process for the depletion or removal of endotoxins from preparations containing active ingredients designated for therapeutical use which are obtained from natural sources by genetic engineering and/or biotechnology by treatment with chromatographic material wherein said natural sources are lysed, the fractions obtained are optionally centrifuged, filtrated or treated with affinity chromatographic methods; said fractions are preincubated with an aqueous salt solution and detergents, treated with anion exchange material and then washed with another salt solution, and the active ingredients are eluted from the anion exchanger, followed by further purification in a per se known manner.