The subject of the present invention is to provide a bioactivator which is useful as a medicine, growth promoting agent for plants and animals, and the like, wherein the bioactive effectiveness of a ferric salt is reinforced and stabilized. One or more kind of vitamin selected from a group consisting of vitamins C, E and K is (are) added to a ferric salt as an anti-oxidizing and bioactivity reinforcing agent, with a magnesium salt being further added as a stabilizer.