Abstract: The present invention relates to a novel method of assaying or evaluating the antioxidizing activities of a living organism or a potentially aggressive agent, said method, which comprises using free radicals as a means of inducing cell lysis, being characterized in that1) a free radical generator is brought into contact, in an appropriate liquid biological medium, with a cell material selected from the group consisting of(a) human, animal and plant cells,(b) fragments of said cells, and(c) synthetic walls and fragments thereof containing liposomes, said cell material having first been contaminated with a potentially aggressive agent;2) the release of free radicals from said free radical generator is induced; and3) the lysis of the cell material by the free radicals is evaluated by comparison with a control containing said cell material which has not been contaminated.