This sums it up quite nicely IMO:
http://www.sequenceinc.com/fraudfiles/2015/03/essential-oils-scam-not-a-medical-treatment/
Here’s the bottom line: Essential oils do not cure illnesses or medical conditions. They possibly make people feel better, and may have a minimal effect on very minor skin conditions. But that’s it. Essential oils won’t heal your cancer, broken bones, migraines, dimentia, fybromyalgia, autism or anything else. And if used incorrectly, essential oils can be dangerous.