The invention relates to a process for purification of a polymeric condensed proanthocyanidin raw preparation obtained from delipidated grape seed waste by staged extraction of phenolic compounds with 96% ethyl alcohol, followed by concentrating the polyphenolic extract up to a density of 1.0...1.1 g/ml and the liquid/liquid extraction with diethyl ether. The process, as claimed by the invention, does not require complex operations, being based on the property of water insolubilization of polymeric proanthocyanidins, to result in a bioactive preparation with a purity of 95%, having antioxidant and antibacterial activity, which can be further exploited in pharmaceutical, cosmetic and food industry.