I took Tea Tree Oil (it was a supposedly very pure brand which I have lost 
the information and source of) internally (it tasted like kerosene or 
gasoline), if I remember accurately, I put  only 7 drops in an 8 oz  glass of 
water daily for a week and  then reduced the drops each week by one (7- 6-   
etc.) but, after the second week it was gone and hasn't returned.. .
Sandy