Thirty-nine extracts of 13 plants used traditionally as medicinal by the Ese'ejas were studied in order to determine their cytotoxic effect in the brine shrimp. Infusions showed no toxicity. Those plants that tested positive for methanolic and dichloromethane extracts were assayed for DNA-binding activity. Cytotoxicity was not due to the presence of compounds that interact with DNA. Antimicrobial activity of plants used to treat infectious diseases was also performed for the decoctions. These proved to be active against some of the test microrganisms used in the assay.