Ayurveda is one of the traditional medicinal systems of Indian culture. The philosophy behind Ayurveda is to prevent unnecessary sufferings and allow us to live a long healthy life. It involves the use of natural elements to eliminate the root cause of a disease by restoring balance between the three doshas (vata, pitta and kapha) within the body. Herbal medicines have existed world-wide since ancient period. World Health Organization (WHO) has estimated that 80% of the world’s inhabitants still rely on traditional medicines for their health care. India is known to be one of the major biodiversity centers with about 45,000 plant species, including 15,000 medicinal plants. The concept of polyherbalism is to achieve greater therapeutic efficacy. The active phytochemical constituents of individual plant are insufficient to achieve the desirable therapeutic effects. This study was conducted to screen the phytochemical constituents and to determine the levels of the major and trace elements of five medicinal plants used for the treatment of diabetes mellitus namely; Aegele marmelos, Catharanthus roseus, Garcinia pedunculata, Musa paradisiaca and Ocimum sanctum. The air dried leaves of the plants were subjected to soxhlet extraction using ethanol, petroleum ether, chloroform and aqueous. The crude extracts were obtained and subjected to screening for their phytochemical constituents such as alkaloids, tannins, terpenoids, reducing sugars, flavonoids, saponins, phenolic compounds and steroids using various standard methods and reagents. Trace metals in the five medicinal plants were analyzed quantitatively using Flame Atomic Absorption Spectroscopy. A digestion procedure involving the use of 4 ml of perchloric acid and 10 ml of aquaregia was performed to digest the medicinal plants. Sterols, tannins, terpenoids, flavonoids, alkaloids, saponins and reducing sugars were identified in the leaves of all the five plants. Elemental concentrations of some of the elements were obtained from the leafy materials in varying quantities. Ten heavy metals (Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, Zn, and V), two alkali metals (K and Na) and three alkaline earth metals (Ca, Mg and Al) and two halogens (Cl and Br) were quantitatively analysed. The anti-diabetic properties of the plant extracts could be attributed due to the presence of steroids, triterpenes and alkaloids. The concentration of toxic metals in these medicinal plants were found to follow the order Fe > Mn > Zn > Cu > Ni > V > Pb > Co > Cr > Cd. Sodium content was found to be very high in G. pedunculata while chlorine content was found to be very high in M. paradisiaca.