Abstract:There is a growing interest of industry to replace synthetic chemicals by natural products with bioactive properties from plant origin. The aim of this study was to validate the therapeutic properties of Mentha pulegium L. by conducting a phytochemical study, to determine the chemical composition of its essential oils (EO) and evaluate its insecticidal activity against stored cereals pests. Leaves and flowers of M. pulegium L.were collected from three regions of the Moroccan Middle Atlas. Phytochemical tests on pennyroyal aerial parts revealed the presence of gallic tannins, flavonoids, alkaloids, sterols and triterpenes and saponins. The chemical composition of essential oils was analyzed by gas chromatography coupled with mass spectrometry. The main components were pulegone and piperitenone. The EO from Khénifra is dominated by pulegone (81.46%), and those from Azrou and M'rirt are rich both in pulegone (68.86 and 71.97%) and piperitenone (24.79% and 26.04%) respectively. Pennyroyal oil has showed an important fumigant effect against Sitophilus oryzae (L.) adults. This effect is influenced by the tested doses and exposure periods. The potential of this plant to be used to control stored product insects was discussed.