Oils are a combiation of isoprene and isopentane alongside many carbon molecules. Many are known as volatile oils, for example menthol, camphor and thujone.
These volatile oils have different properties:
Camphor=promotes digestive juice release and stimulates digestive tract
Thujone = antiseptic.
Some general properties associated with Volatile oils include antiseptic, antibacterial, anti-fungal, insect repellent, anti-spasmodic, anti-inflammatory etc.