What is your evidence for this, Fejal? What studies have been done? Which oils in particular are you referring to? Toxic in what sense?
Jenny
Every bottle of essential oil states that they are for external use only and can only be used if they are diluted with a base oil or other carrier. One I read said that it can cause permanent lung damage.
I don't know the specifics for oregano oil but one animal research article only listed it for external use so I tend to think that it's a good idea to assume toxicity in light of the concentration. Given that there are proven drugs to kill the bug it just doesn't make sense to use it. I can see people who do as desperate due to being undiagnosed and not under the care of a physician. I doubt any MD would prescribe it internally.