The invention relates to the use of a composition comprising at least one extract of propolis, having at least one of the following properties: —an antioxidant value (ORAC) greater than or equal to 500 mmol TE/100 g of dry extract, —a flavones and flavonols content greater than or equal to 5.5% by weight with respect to the total weight of dry material of the extract, —a flavanones and dihydroflavanols content greater than or equal to 5% by weight with respect to the total weight of dry material of the product, in order to prevent and/or limit the side effects of chemotherapy.