A total of 123 fungus strains of the Fusarium genus were found in 181 samples of maize. Fusarium moniliforme was most frequently isolated. It was found that 14 of the strains produced F-2 toxin. Experiments were carried out with 50 male and female guinea pigs. Each of the test animals was given orally 0.2 ml (daily, in the course of twenty days) crude toxin obtained through growing the fungus--selected strains--on sterile maize flour. It was established that most of the tested toxins affected the reproductive apparatus of the animals, causing necrobiotic and degenerative changes. Some Furarium species even produced toxic substances that manifested tropism to the digestive tract, liver, kidneys, heart, the nervous system, where they caused hemodynamic troubles and degenerative changes.