The invention relates to an avocado extract rich in polyphenols, containing at least 10% by weight of polyphenols, expressed in gallic acid equivalent relative to the dry extract obtained, wherein said polyphenols contain procyanidins, cafeic acid and cafeic acid derivatives, typically in a proportion of at least 70% by weight, expressed in gallic acid equivalent relative to the total polyphenol content by weight. The invention also relates to a composition comprising an extract according to the invention as active agent and a suitable excipient. The invention also relates to such a composition or such an extract for use thereof in preventing or treating disorders or pathological conditions of the skin, the mucous membranes or the superficial body growths. Finally, the invention relates to a cosmetic care process for the skin, the superficial body growths or the mucous membranes, with a view to improving the condition thereof or the appearance thereof, which consists in administering such a composition or such an extract.