Abstract: The present disclosure describes a study of estrogenic activity present in various plant species, selectively inducing some but not all estrogenic responses in the uterus. Prepubertal female rats were treated sequentially with various extracts or decoctions of different plant species or its vehicle, followed 1 h later by treatment with estradiol-17? (E) or its solvent. Uteri were excised under anesthesia and histologically processed for eosinophil quantification and morphometric evaluation of various uterine responses to estrogen, at 6 or 24 h after hormone or vehicle treatment. Besides extracts or decoctions, pure phytoestrogens were also used. Additionally, human mammary cancer cells MCF-7 or MDAMB-231 were cultured in presence of the extract (or decoction), E, both or solvent and cell proliferation was evaluated.