There are lots of EO's that you would practically have to drink to get any adverse effects: lavender, lemon, orange, peppermint, litsea cubeba, etc. There are a lot of dangerous ones, but most are safe if used in sensible quantities. Almost anything can be dangerous if used incorrectly. FO's on the other hand, in my opinion, are not as safe as everyone seems to think. There are lots of people who have problems with chemical scents, who have no problems with EO's. I was once sick for a week, felt like my lungs were on fire, from a 1 minute exposure to a highly scented candle. I use EO's all the time, as room sprays, in my soaps, in bath salts, in water simmering on the wood stove, and have never had a problem. I have a shop in which I sell my soaps and bath salts, along with lots of unscented things, and we've had people come in and tell us that it is nice to be able to shop in a store that doesn't stink to high heaven from the masses of scented products that most other stores seem to carry these days. Many people like highly scented candles and soaps, but there are many, like myself, that dislike them, and many that get very sick from any exposure to them. If your friend wants something "natural", EO's are the way to go.