Niaouli is a strong antiseptic, antibacterial oil. It also has strong decongestant properties, which make it appropriate for treating head and chest colds. In addition, it helps clear the head mentally, as well, since it has a stimulating and uplifting effect.
Some sources recommend it for fighting acne, boils, and other skin infections. I have also seen it recommended for treating cystitis.
SHELF LIFE: Approximately 2 to 3 years after you open the bottle. Storing in the dark, refrigerated, and decanting half full bottles into smaller, full bottles will extend shelf life.
Image courtesy of Steven Foster.