This study assessed the cytotoxic and genotoxic potentials of extracts of Psittacanthus acinarius (Mart.) Mart. and Psittacanthus cordatus (Hoffmanns.) in the root cell cycle of Allium cepa L. Aqueous leaf extracts of P. acinarius and P. cordatus at three concentrations: 0.00, 5 and 20 mg/mL for 24 hours. Histological slides were prepared and mitotic indices (MI %) and chromosomal alteration indices (CAI %) were determined. Inhibitory effects of the aqueous extract of leaves of P. acinarius were observed in 46.33 and 46.00% at concentrations of 5 and 20 mg/mL, respectively, in relation to the control (62.83%), in addition to a higher chromosomal alteration index by 0.26% at a concentration of 20 mg/mL. In the aqueous extract of leaves of P. cordatus, the greatest inhibitory effects were 33.83 and 35.50% in the concentrations of 5 and 20 mg/mL, respectively, in relation to the control (88.16%) and the highest alteration index chromosomal (3.30%) at 5 mg/mL. The aqueous leaf extracts of P. acinarius and P. cordatus at concentration of 5 and 20 mg/mL inhibit MI %, reveal an irregular recovery or prevent it, and induce chromosomal alterations, suggesting cytotoxic and genotoxic effects on division of meristematic cells of A. cepa.