I think the OP was talking about tea tree oil, but I have to agree with Chanley, some herbal teas can be a great help in fugal/yeast infections
dd had a yeast infection from day3 untill 2-3 months old: it would disapear for a few days with canesten and other yeast treatments or gentian violet, but it would come back 2-3 days after the end of the treatment, no matter how long I used it, so I went to see an herbalist, and she made me an herbal mixture: camomille, black walnut (antifungal), chickweed and comfrey
pour 1 cup boiling water over 1tbs herbs, let sit for 15-20 minutes, drain, use as a wipe solution.
I also threw some herbs in my dd's bath.
Not only did the yeast go away in 2 days, it never came back (I used this for a month or 2, but since it is non invasive, natural, cheap, it didn't bother me)
I also took an antifungal herb concentrate (dd is breastfed) that has garlic, wormseed, cayenne pepper, echinacea, black walnut and stingning nettle macerated in apple cider vinegar.
dd has super sensitive skin and tto in her wipe solution (even 1 dropo for 2 cups of water) gave her a rash
HTH