The effects of the food additives monosodium phosphate (MSP), disodium phosphate (DSP) and trisodium phosphate (TSP) have been studied on root tips of Allium cepa L. Roots of A. cepa were treated with a series of concentrations, ranging from 300 to 500 ppm for 24, 48 and 72 h. The results indicated that these food preservatives reduced mitotic division in A. cepa when compared with the respective control. Mitotic index values were generally decreased with increasing concentrations and longer treatment times. Additionally, variations in the percentage of mitotic stages were observed. The total percentage of aberrations generally increased with increasing concentrations of these chemicals and longer period of treatment. Different abnormal mitotic figures were observed in all mitotic phases. Among these abnormalities were stickiness, anaphase bridges, C-mitosis and micronuclei. These food additives remarkably depressed the DNA content in the root meristems of A. cepa. The interphase nuclear volume (INV) also varied between the untreated (controls) and the treated plants.