Two novel pyrrolidine compounds, conioidines A [1] and B [2], have been isolated from the Texas plant, Chamaesaracha conioides (Solanaceae). Their structures were determined by spectroscopic methods and hydrolysis studies. Both natural products, like doxorubicin, showed DNA-specific KB cell cytotoxicity. Dose-response data indicated a Kd value of 2.8 microM for binding of conioidine A [1] to calf thymus DNA.