Eucalyptus globulus, a plant from family myrtaceae, commonly known as blue gum, grows well in different parts of world and has been known since decades because of its rich ethanomedicinal and therapeutic importance. The aim of this study is to determine the oil content variation, characterization and antimicrobial properties of the essential oils of Eucalyptus globulus grown in Saharanpur region (Uttar Pradesh). The leaf oil from Eucalyptus globulus tree obtained by hydro - distillation significantly containing their oil content from the range 0.6% to1.04% v/w. The chemical constituents of essential oil were analysed by Gas Chromatography – Mass Spectroscopy (GC - MS). Twenty compounds were characterized in the oil and the main components of the essential oil were Eucalyptol, α– Terpineol, gamma-Terpinene, Alloaromadendrene, Epiglobulol, (-)-Globulol, (-)- Isolongifolene, Nerolidol. The results of the antimicrobial activity tests revealed that the essential oil of Eucalyptus globulus has antimicrobial activity, especially against bacterial strain Pseudomonas. Aeruginosa (MTCC 2642) i.e.11.50mm 20 μL of oil/disc and fungal strain Candida. Albicans i.e 12mm 20 μL of oil/disc.
