Tynanthus micranthus, a plant species belonging to family Bignoniaceae, is widely used on the northwest region of Paraná state as stimulant and aphrodisiac. The lack of studies about this specie motivated the research for phytochemical evaluation and some biological activities of the plant. Toxicity studies of the ethanolic extracts and fractions of the species investigated were performed in Artemia salina eggs in addition to antimicrobial activity of the ethanolic extracts against species of some bacteria strains. The results indicated the presence of β-sitosterol steroid in the hexane fraction and apigenin flavone in the chloroform fraction, both isolated from the stalk. Some fractions developed toxicity over Artemia salina and its extracts showed to be lethal causing death of certain bacterial strains.