DO NOT EAT TEA TREE OIL! ITS POISON AND FOR EXTERNAL USE ONLY! Thrush is an overgrown of yeast in the mouth due to an imbalance of bacteria. Common causes of Thrush are: Oral antibiotics, immune deficiency diseases, and possibly over cleaning your mouth. Eat Yogurt and see a doctor and stay on your meds. Salt water and vinegar and water wont do much. Orange Juice, orange juice, orange juice! ... View related article.