Fusaric acid (FA) is produced by several Fusarium species and is commonly found in grains. This investigation was performed to evaluate the cytotoxic and genotoxic effects of FA either in human cervix carcinoma (HeLa) cell line using 3-(4,5-dimethylthiazolyl-2)-2,5 diphenyltetrazolium bromide (MTT) assay and in human lymphocytes using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), micronuclei (MN) as well as comet assay in vitro. The cells were treated with 0.78, 1.56, 3.125, 6.25, 12.50, 25, 50, 100, 200, and 400 mu g/mL concentrations of FA. It has potent cytotoxic effect on HeLa cell line measured by MTT assay especially at higher concentrations (200, 400 mu g/mL). The half of inhibitory concentration (IC50) evidenced by FA in the HeLa cells was 200 mu g/mL at 24 h and between 200 and 400 mu g/mL at 48 h. It was also observed that FA produced a significant decrease in mitotic index (MI) at 12.50 mu g/mL compared to solvent control. Furthermore, it indicated a cytotoxic effect at the concentrations ranging from 25 to 400 mu g/mL in human lymphocytes. The results of this research point out that being exposed to FA at high concentrations show cytotoxicity. Besides FA induced comet tail intensity at 3.125, 6.25, and 12.50 mu g/mL concentrations in isolated human lymphocytes. On the other hand, no genotoxic effects were seen in human lymphocytes in vitro using CA, SCE and MN assays.