Tea tree oil is austrailian Melaleuca alternifolia oil.  On the list which
came with my bottle, there is no mention of it helping thrush, but is
supposed to be good against pimples and other skin impurities.  It tastes
awful, so for that reason alone I wouldn't put it on my nipples in any
case!  (would certainly keep a man at his distance!) My 13 year old will
not drink it with 1 drop diluted in a glass of water.  There is a new hand
cream made with it too.  Afriend used it and her 10 year old complained of
the smell.  

Anne Kaeser, BA, IBCLC
Germany