The invention relates to an extract from the flowers, preferably from the calyxes, of Bombax costatum, to a process for preparing same and to the extract obtained by said process. The invention also relates to a composition comprising such an extract, the composition advantageously being a cosmetic, pharmaceutical or dermatological composition. The invention also relates to such a composition or such an extract for the use thereof in preventing or treating disorders or pathological conditions of the skin, the mucous membranes or the hair and nails, as well as the imbalance or disorders associated with the imbalance of the microbiota of the skin, the mucous membranes, the hair, the nails and associated skin appendages. Finally, the invention relates to a cosmetic care method for the skin, the hair and nails or the mucous membranes, with a view to improving the condition or the appearance thereof, which method consists in administering such a composition or such an extract.