Eucalyptus oil harvested from the fast-growing evergreen by the same name is native to Australia. The tree has also been introduced in India, Europe and South Africa. The distilled oil derives from leaves of the tree and is colorless with a distinctive taste and odor. The name derives from the protective cap on the unopened flower. Eucalyptus oil maintains properties of typically volatile oils.
Primarily, this oil finds use in its medicinal properties. The chemical compound eucalyptol is believed to help control blood sugar, fight bacteria and fungi, and decrease pain and inflammation. Eucalyptus oil should be diluted for safety when used topically or orally. Taken by mouth, this oil is reported to reduce inflammation in the respiratory tract, act as an expectorant, and treat wounds, burns, ulcers and cancer. Applied topically, this compound reduces pain and swelling of respiratory tract mucous membranes and joint pain. Eucalyptus oil is also used as an insect repellent.