Available online A B S T R A C TPlantago genus has a wide geographical distribution all over the world. It has been widely used in folk medicine for various purposes, where it is used as anti-inflammatory, antimicrobial and antitumor agent. In this research, total phenols, tannins, saponins, flavonoids and alkaloids were determined in Plantago lagopus, Plantago major and Plantago squarrosa.Furthermore, concentrations of 2.5, 5, 7.5 and 10 mg ml −1 of both alcoholic and aqueous extracts were prepared to study their phytotoxic effect on the germination and seedling growth of the noxious weed Bidens pilosa. P. major expressed the highest values of total phenolics, tannins and flavonoids. However, P. lagopus has the highest content of alkaloids. The germination of B. pilosa was completely inhibited under treatment of P. lagopus and P. major methanolic extracts at 7.5 mg ml −1 and 10 mg ml −1 , respectively. However, the allelopathic effect of P. lagopus aqueous extract showed a complete inhibition of B. pilosa germination followed by P. major. The germination inhibition of B. pilosa increased with the increase in the extracts concentration. In addition, both radicle and plumule were strongly inhibited under the same treatment. Our results showed a potent allelopathic effect on B. pilosa that could be valorized in managing this noxious weed as an ecofriendly bio-control method.However, other studies are needed for the identification, characterization of the responsible allelochemicals and for the demonstration of their modes of action. Production and hosting by Elsevier B.V. on behalf of Mansoura University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/bync-nd/4.0/).