The invention relates to an insecticide and/or insect-repellent method according to which a composition containing at least one constituent having insecticide properties targeting biting insects and/or repellent properties targeting an insect in the surroundings of a human being or animal is orally administered to said human being or animal, all or some of said at least one constituent being found as is in a body liquid such as the blood, perspiration or lymph of said human being or animal. The invention is characterised in that the at least one constituent is selected from a molecule such as citronellol and citronellal and/or an essential oil selected from lavandin grosso, citronella, clove and geranium.
