Adenoids and tonsils are often talked about together. You can see your tonsils in the back of your throat, but where are your adenoids? For that matter, what are your adenoids? Let's find out. What Are Adenoids? The adenoids (say: add-eh-noids) are a patch of tissue that sit in the back of the nasal cavity. Although you can easily see your tonsils by standing in front of a mirror and opening your mouth wide, you can't see your adenoids this way. Like tonsils, adenoids help keep your body healthy by trapping harmful bacteria and viruses that you breathe in or swallow. Adenoids do important work as infection fighters for babies and little kids.