The present application relates to a process for preparing an extract of leaves of Vitis vinifera L. comprising the following steps:a) preparing a drug from leaves of Vitis vinifera L.b) extracting the drug with an eluant selected from among water and mixtures of water with alcohol, to obtain a raw extract,c) separating the raw extract from the extracted drug,d) at least partly eliminating the eluant, to obtain a thick extract,e) redissolving the thick extract in water,f) separating off any insoluble constituents,g) selectively concentrating secondary plant ingredients by i. a 2-phase extraction orii. membrane filtration；the extract that is obtainable therefrom, pharmaceutical preparations containing this extract and the use thereof.
