Causes

Normally, your immune system works to repel harmful invading organisms, such as viruses, bacteria and fungi, while maintaining a balance between "good" and "bad" microbes that normally inhabit your body. But sometimes these protective mechanisms fail, increasing the number of candida fungus and allowing an oral thrush infection to take hold.

The most common type of candida fungus is Candida albicans. Several factors, such as a weakened immune system, can increase your risk of oral thrush.