Antimitotic agents induce pathological alterations by suspension of the normal cellular renewal: it results the picture of the so called « aregenerative pathology ». Moreover, they induce cytological abnormalities, like cellular vacuolization, alterations of the enzymatic cellular pattern, cellular giantism, etc. These alterations constitute the « cytological dysplasia by antimitotic drugs ». They are easily recognizable in many organs, i.e. in the haemopoietic system, lungs and pancreas. Particularly evident is the cellular giantism in the labial epithelia: in some of these cells of gynecologically normal women two Barr bodies are observed.