The effects of fusarial toxins: DAS, T 2, DON, 3 Ac DON, MON and ZEA, on actively dividing root tip cells of rye, wheat and field bean were investigated. Three concentrations: 1, 5 and 10 mg mL-1 were applied for 24 hours. Nuclei and chromosomes were stained using the Feulgens method. It has been found that trichothecene mycotoxins (DAS, T 2, DON, 3 Ac DON) had a profound effect on mitosis, as they decreased the mitotic index, produced excessive condensation of pro and metaphase chromosomes, C metaphases and C anaphases, and caused an accumulation of metaphases. The main effect of trichothecene mycotoxins, probably caused via their influence on protein synthesis, was abnormal functioning of the mitotic spindle.