Actually, lavender is not safe for certain individuals and especially not for use by pregnant women. I am not sure about nursing women but I would not even think about recommending it to one. OG is right, essential oils need to be studied for safe use in any application. Plus each application type has its % rates for different applications so you need to know these too. If you are going to sell oils for a diffuser you should also purchase the oils only from a reliable source that also discloses origin, purity, production, certification, IFRA info, etc. its much better, cheaper, and safer to use FOs especially if you are going to start selling them to the general public. Also, the oils typically need to be diluted with a carrier oil or DPG.