Antifungal composition comprising a hydrolysed ellagitannin-based natural chestnut extract.Said antifungal composition is particularly recommended for fighting diseases caused by: Plasmopara viticola, Phytophthora infestans, Bremia latucae, Pseudoperonospora cubensis, Peronospora destructor, Podosphaera xantii, Golovinomyces fuliginea, Erysiphe polyphaga, Erysiphe oronti, Spheraerotheca fuliginea, Leveillula taurica, Oidium lycopersicum, Erysiphe sp, Botritys cinerea, Venturia inaequalis, Anthracnose of grapes, Phomopsis sp., Podosphaera leucotricha, Oidium farinosum, Uncinula necator, grape black rot and Pseudomonas syringae, in the cultivation of actinidia, in crops in general, in horticultural, fruit and agricultural crops in general, in vegetable and garden plants and in agricultural soils.