• Vegetable or Base Oils

• Essential oils in a pure state are too highly concentrated  to be used directly on the skin, therefore the essential oils are diluted in a base oil, so that they can be massaged or rubbed into the skin in the correct dosage. One drop of essential oil may be all you need to use. That obviously will not go very far, but when diluted in a base oil the mixture will cover quite a large area.
• Base oils are vegetable , nut or seed oils, many of which themselves have therapeutic properties. Vegetable oils are obtained from the seed of plants that grow all over the world. There are several hundred different plants known to have oil-bearing seeds, but only a few a produced commercially.
• Vegetable oils are in the main produced for food, and are good sources of nutrients and energy. They enable the body to produce heat and are good sources of protein, as well as providing lubricants  and cooking materials  for industry and home use.
• 
  The vegetable oils used in aromatherapy should be cold pressed, as the oils on your supermarket  shelves may have been pressed with a chemical agent.
• Use the following measurements  as a guideline when diluting  the essential oils in a vegetable base oil.

 Reference: Fragrant Pharmacy/ V Worwood