Sources of vegetables purchased for consumption in communities in Nigeria as well as their level of contamination or bioaccumulation of toxicant is not always known. This study evaluates the proximate analysis of Solanum aethiopicum (L), Lactuca taraxacifolia (Willd) and Talinum triangulare (L) purchased from Sabo market in Ogbomoso, Nigeria. The potential cytotoxic effect of their aqueous extracts was also tested on Allium cepa (L). The proximate analysis revealed that the vegetable contained valuable nutrients that are needed for body development. The protein and moisture contents were significant in S. aethiopicum and T. triangulare respectively. The heavy metal evaluation showed the presence of iron, zinc, lead, and copper ions at various degrees in the vegetable extracts with significant difference observed in all except for lead. The extract of the vegetables showed significant inhibition of A. cepa root length at 10.0, 25.0 and 50.0 ppt of S. aethiopicum, 25.0 and 50.0 ppt of L. taraxacifolia and only 50.0 ppt of T. triangulare compared to control (P<0.05), while the EC50 values of 5.7, 14.0 and 22.4 ppt which reflected the order of their toxicity were respectively obtained. Variations in the value of Mitotic index and inhibition were obtained with various chromosomal aberrations observed in the extracts at different concentrations. The results revealed that the tested extracts possess inhibitory, and mitodepressive effects on the root growth and cell division, and also induced chromosomal aberrations in A. cepa. The vegetables might have bioaccumulated toxicants which may hitherto affect the consumers.