Abstract: A method for increasing the bioavailability of antiparasitic active ingredients, and therefore to potentiate the effects thereof, including combining antiparasitic active ingredients with an adjuvant, wherein, the antiparasitic active ingredients are capable of being recognized and binding to cellular transporters in order to be transported out of cells without being able to reach an intracellular therapeutic target, the transporters being present in the cells of the human or animal organism to which the antiparasitic active ingredients are administered, and, optionally, in the cells of parasites against which the antiparasitic active ingredients are administered, the adjuvant is a compound corresponding to fumagillin of the following formula (II):

Abstract: The invention relates to the use of fumagillin and the analog derivatives thereof, as inhibitors of cellular transporters, such as ABC transporters, and especially of P-glycoprotein, in order to increase the bioavailability of active ingredients that can be used in the treatment of pathologies such as cancers or parasitic diseases, and especially in order to increase the bioavailability of the macrocyclic lactones.