Conifers, “Trees of the records”, contain an extraordinary collection of species, represent one third of the world’s forests, and their origins go back up in the mists of time. A pyramidal port, leaves in needles, fruits in cones and especially the resin make the main characteristics of these species. The ecological plasticity and high wood quality as well as their non-ligneous forest products (resin and rosin) confer remarkable ecological and economic interests to these species. Although the traditional medicines originating from conifers have always showed their efficiency through the history, they still remain badly known. The essential oil of the Fir tree of Numidia (Abies numidica) from the region of Seraidi (Annaba) was the topic of our work. The chemical identification of essential oil revealed their wealth in terpene compounds of which the monoterpenes had shown the highest content. The research for the antibacterial activity of various studied samples showed variable results regarding the drug and the tested origin. A good antibacterial activity was noticed for essential oil.