Solanum cernuum VE. has been used extensively for the treatment of urinary disorders, gonorrhea and skin infections; cernumidine is a major component of S. cernuum (SC) hydroalcoholic extract. The micronucleus test in V79 cells was used to evaluate the genotoxic and antigenotoxic potential of SC and cernumidine. For antigenotoxicity assessment, methyl methanesulfonate (MMS, 44 µg/mL) and hydrogen peroxide (H₂O₂, 3.5 µg/mL) were added as inducers of chromosome damage. Antioxidant activity was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test. Significantly higher frequencies of micronuclei were observed in cell cultures treated with SC concentrations of 160 and 320 µg/mL in comparison with the negative control, demonstrating a genotoxic effect. There was no significant difference in the frequency of micronuclei between cell cultures treated with a combination of SC and MMS and those treated only with MMS. On the other hand, a significant reduction in the frequency of micronuclei was observed for V79 cells treated with SC or cernumidine plus H₂O₂ compared to those treated only with H₂O₂. Furthermore, SC and cernumidine were able to scavenge free radicals in the DPPH assay. Thus, the protective effect of SC and cernumidine against H₂O₂ can be attributed to antioxidant activity.