In the article the peculiarities of the influence of fodder additives HammecoTox and Zeolit on the organism of rats under conditions of experimental chronic fumonisin toxicosis are given. The research was carried out under vivarium of State Scientific-Research Control Institute of Veterinary Medicinal Products and Feed Additives. In the experiment, 40 rats of body weight 165–170 g. were used. 4 groups were formed. First group of animals was control, in experimental II, III, and IV groups of animals chronic fumonisin toxicosis was reproduced. Rats were injected intragastrically daily of 90 mg of fumonisin per animal. After the manifestation of clinical signs of fumonisin toxicosis on the 21st day, animals of groups ІІІ-ІV began to feed fodder additives, respectively, rats from group III – HammecoTox, IV – Zeolit. After injection of fumonisin to experimental rats, the morpho-functional state of animals has been gradually changing since the first days. Clinical picture of fumonisin toxicosis in experimental rats at day 14 was manifested by dermo-necrotic effect, it was observed redness and formation of crust on visible mucous membranes, nose, showed swelling and redness of the forelocks. After the analysis of the obtained results of hematological researches on the 14th day in rats of group II under the conditions of experimental fumonisin toxicosis, was revealed a probable increase in the number of leukocytes, was established a tendency for growth, the number of eosinophils, segmental neutrophils, as well as a decrease in the number of lymphocytes, monocytes, compared with the control group. In the analysis of leukograms was noted a tendency to shift the nucleus to the left. These results indicated the presence of inflammatory processes and reduced immune protection of the organism of animals in general. After using of feed additives of HammecoTox and Zeolit under conditions of fumonisin toxicosis, of particular note is the stabilization of hematological parameters, the content of hematocrit, the number of leukocytes, the increase in the content of eosinophils and lymphocytes, which reflects the activation of hematopoiesis in the organism of experimental animals and its protective factors. An increase in the urea content in these groups indicates the recovery of urea-synthesis and urea-excretory liver function. In general, for the period of the conducted searches, the effectiveness of both feed additives in the experimental fumonisin toxicosis has been established. However, it should be noted that more active processes of normalizing the clinical condition of experimental rats when using HammecoTox, which is due to the complex influence of the means on the organism of animals.