Chenopodium sp. (Chenopodiaceae), common name “Paico,” is a medicinal plant that has been used for centuries as an antirheumatic, anthelmintic, sedative, and analgesic agent and as a spice in food. The main component of the essential oil is ascaridole. The aim of this work was to evaluate the possible cytotoxic effects of aqueous extracts of Chenopodium ambrosioides L. (ten specimens from different parts of the country), Chenopodium multifidum L. (three specimens) and to compare them with a nonaromatic Chenopodium (Chenopodium album). The extracts [decoction (D) and infusion (I)], which are the usual way of consumption by the population] were assayed by mitotic index in different concentrations (0, 1, 10, 100, and 1000 µg dried plant/mL of culture), on lymphocyte cultures from four healthy donors, as a cytotoxicity biomarker. One-way analysis of variance (ANOVA) test was performed. The results show a statistically significant decrease in all the specimens of C. ambrosioides and C. multifidum, whereas no effect was observed in the analysis of C. album. These results suggest a cytotoxic effect of C. ambrosioides and C. multifidum aqueous extracts related with the essential oil of the plant.