The chalcones (E)-3-(4-chlorophenyl)-1-phenyl-2-propen-1-one (4-CL) and (E)-3-(3,4-dimethoxyphenyl)-1-phenyl-2 -propen-1-one (DMF) are versatile and easily synthesized into low-cost compounds that have a wide spectrum of biological activities. In this study, the cytotoxic, genotoxic and modulatory activities of 4-CL and DMF were evaluated using the Ames test and the mouse micronucleus assay. The results of the Ames test revealed that both chalcones did not show mutagenic activity in Salmonella typhimurium strains TA98 and TA100, and demonstrated significant antimutagenicity (p< 0.05) when co-administered with sodium azide (SA) in strain TA100. In the micronucleus assay, both showed a significant increase in the frequency of micronucleated polychromatic erythrocytes (MNPCE) at 24 h and 48 h, revealing a genotoxic effect. In the co-treatment with mitomycin C (MMC) there was a significant decrease (p< 0.05) in the frequency of MNPCE both in chalcones at 24h and in the less concentrated dose of DMF at 48h, demonstrating its antigenotoxic activity. 4-CL showed a significant decrease in the polychromatic/ normochromatic erythrocyte (PCE/ NCE) ratio at 24 and 48 h (p< 0.05), indicating cytotoxicity. However, 4-CL and DMF when co-administered with MMC showed a significant increase in the PCE/NCE ratio within 24 hours, demonstrating anticytotoxicity. Furthermore, a biphasic dose-response behavior was observed in both chalcones, 4-CL in the co-administration with SA, in the Ames Test and DMF in the co-treatment with MMC, at 48 hours of exposure, in the micronucleus assay. In this study, 4-CL and DMF showed genotoxic, cytotoxic, antigenotoxic, anticytotoxic and no mutagenic properties.