Thrust infection related to the mouth infection caused due to the candida fungus, also called yeast. This candida infection may occur at any part of the body and cause diaper rash among infants or vaginal yeast infections to women. It mostly and easily affects babies and toddlers, old-aged people and people having weak immune systems. There are small quantities of candida fungus present inside the mouth, digestive tract, and on the skin of healthy people. Nevertheless, there are certain illnesses or medications that disturb the balance of microorganisms and cause the fungus candida to develop beyond control, thus causing thrush that includes antibiotics, corticosteroids and birth control pills. Smoking or use of unfitted dentures can also increase the risks. Besides, babies can pass the infection to their mothers at the time of breast-feeding.