It has been traditionally considered that catechols release iron from ferritin by reduction to iron(II), which diffuses through the ferritin channels into the intracellular milieu where it participates in the Fenton reaction, producing highly toxic hydroxyl radicals. However, in the present work we have proved that the mechanism of the release of iron from ferritin by catechol does not take place by iron(II) reduction but by direct iron(III) chelation and therefore without iron(II) production. A possible extension of these findings to other catechols is discussed on the basis of the stability with respect to the internal redox reaction of the iron(III)-catechol complexes.