Some compound refering to the 3-hydroxy-1,5-diaryl-4-pivaloyl-2,5-dihydro-2-pyrrolones have been found to cause an increase in the number of mitotic cells and their subsequent death in vitro. This increased in the number of mitotic cells was not associated with increased cellular proliferative activity and was likely due to mitotic exit failure. Of note, the effect was more pronounced in the tumor cells when compared to human fibroblasts. Further studies are needed to investigate the molecular mechanisms of action of the compounds belonging to the class of 3-hydroxy-1,5-diaryl-4-pivaloyl-2,5-dihydro-2-pyrrolones.