Abutilon theophrasti Medik., velvet (Malvaceae) was pharmacognostically investigated aiming to establish its morpho-anatomical characteristics (root, stem, leaf, flower) and leaf chemical composition. A phytobiological test (Triticum test) assessed the activity of two extracts prepared from leaves (aqueous extract 5.00 - 0.033 % w/v and total extract of polysaccharides 1.00 - 0.006 w/v %) on plant cell division. The following histo-anatomical elements were observed: secondary structure with dilated rays (root); incomplete secondary structure (stem); sclerenchymatous fibres (root, stem); dorsi-ventral (bifacial) structure with two-layered palisade tissue, druses of calcium oxalate, unicellular trichomes forming star-shaped groups, glandular hairs (leaf); and androspore with echinate exine and endothecium (flower). Carotenoids, sterols, triterpenes, rutin, polyphenolcarboxilic acids, condensed tannins, mono - and polysaccharides and reductive compounds were identified. Leaves contained 7.01 - 7.02 g % polysaccharides, 0.45 - 0.60 g % flavones (expressed as rutin) and 0.22 - 0.48 g % polyphenolcarboxilic acids (expressed as caffeic acid). The aqueous extract (5.00 - 0.33% w/v) and polysaccharides fraction (1.00 - 0.5% w/v) inhibited the Triticum root growth (the aqueous extract more intensely); a mitoinhibitory activity was observed, with metaphases and telophases in tropokinesis, anaphases and telophases with bridges and bent membranes.