I don't advice you to use Grapefruit-Seed-Extract direct on your tongue. You should take it internally. Again, a white tongue isn't because the infection is on it but internally. You can have candida on your tongue but that is another thing. I had a white tongue since I was very young and was the strongest man on earth. Now, my tongue is almost pink and I feel like crap. So, if you feel good , forget your tongue color for a while. You may do more damage than good experimenting things.
Jorge.