The tonsils are a pair of structures that are found on both sides of the mouth, in the back, by the base of the tongue. The adenoids are not usually visible by looking in the mouth. They are a mass of tissue located above the roof of the mouth at the back of the nose. Both the tonsils and adenoids are felt to be components of our immune system. When they’re healthy and functioning normally, they help fight infection that enters our body through our nose or mouth. Removing the tonsils and/or adenoids doesn’t make us more likely to catch infections, as there are many other immune defense structures in our upper airway that act in their place. As we get older, the tonsils usually shrink in size and the adenoids vanish entirely. There is a wide range of normal size for both of these organs.