Are there any rules for using essential oils?

Holistic healer Hope Gillerman answers:

1. Go by the numbers. For the best effects, "Use essential oils in a blend of three to five oils, not one oil at a time."
2. When in doubt, dilute. Many essential oils are too concentrated to apply directly to skin--they need a carrier oil. Essential oils diluted in botanical oil extracted from a nut or a seed (like avocado, kukui, coconut, sunflower or almond) are suitable for covering a larger area of the body or for using in the bath. For those oils safe enough to apply undiluted, "They must be used only one drop at a time." (Ask an expert to determine which oils are safe).  
3. Stay in this area. For an essential oil diluted in carrier oil, the neck, shoulders and chest are the best areas to absorb essential oils. Hands and feet are also good ways to test out an oil for sensitivity or to absorb an oil that could be irritating on the neck and shoulders.
4. Learn to breathe. For a quick fix, try this way to do an inhalation: put one drop of a 100% blend or a few drops of a diluted blend in the center of each palm. Then rub palms together, cup them over your face and inhale deeply ten times. It will feel great!"

Source: Hope Gillerman, certified Alexander Technique teacher, holistic healer and creator of H. Gillerman Organics essential oil remedies and HGO Lab Skin Care