Are you talking thrush as in, a vaginal yeast infection? If so- you can use monistat. And any other creams, like vagisil. The only time Ive had thrush down there was when Ive been pregnant, and the Monistat works like a charm. Good luck!
(Also, its best to use the internal creams at night, because it stays in there longer. When you are up walking around, obviously it comes out. )