The effects of different treatments with food preservatives, sodium propionate (SP), calcium propionate (CP) and potassium propionate (PP), on the cytology and DNA content of Allium cepa were investigated. Five concentrations of these additives - 1000, 1500, 2000, 2500, and 3000ppm - were applied for 24, 48, and 72h. All concentrations of these chemicals showed an inhibitory effect on cell division in root-tips of A. cepa and caused a decrease in mitotic index values. Additionally, all treatments changed the frequency of mitotic phases when compared with the control groups. These compounds increased chromosome abnormalities in test material. Among these abnormalities were C-mitosis, anaphase bridges, micronuclei, binucleated cells, stickiness, laggards, and chromosome breaks. The nuclear DNA contents decreased when compared with control groups.