I've never come across lobelia oil - only the tincture - you could use lobelia tincture and mullein oil - one on top of the other, if that is all you had. In order to get the dried lobelia, you will have to go to an herb store that carries dried herbs in bulk or go on line. Most health food stores are not much more than vitamin stores, so you will have to find someone who specializes in herbs. Once you do, these are excellent items to keep in storage so you will have them when you need them.