Your dentist knows before he asks if you floss regularly or not, but he can also spot signs of serious issues, like chronic infections, anemia and celiac disease. Your mouth provides a clear window into your health and your dentist can identify when it’s time to be concerned. Here are four symptoms that might have your dentist suggesting a doctor’s visit:

Bleeding gums: “If you floss or brush too hard your gums will bleed a little,” says Dr. Jack Slome, a dentist in private practice in Toronto. “But if your gums bleed easily and frequently then it can be a warning sign for diabetes.” High glucose levels in the blood feed the bacteria that cause plaque and irritate gums, which makes them more prone to bleeding when brushed.

Swollen tongue or inner cheeks: Unexplained inflammation in the mouth is a common initial symptom of anemia due to vitamin B12 deficiency, says Dr Euan Swan, a dentist and the manager of Dental Programs at Canadian Dental Association in Ottawa. Anemia is a lack of healthy red blood cells and can zap your energy and leave you with headaches and dizziness. “Other signs of vitamin B12 deficiency are re-occurring oral ulcers, pale appearances on the inside of the cheek or an oral fungal infection.”

Bad breath: You can usually blame this on the extra garlic on your pasta or—more embarrassingly—food caught in your teeth, says Dr. Slome. A few days of consistent brushing and flossing should clear it up. If not it’s time to see a doctor. You might have a local infection in the respiratory tract, a sinus infection, postnasal drip, bronchitis, or a digestive problem, says Dr. Slome. “The stench of breath is caused by bacteria. If you have an infection there might be bacteria caught in the pits and grooves in the back of your mouth and throat, which makes your breath smell,” he says.

Discoloured, blotchy or translucent enamel: Problems with the enamel of teeth is a sign of celiac disease, which is a digestive disorder marked an intolerance to gluten. “Because the disease damages the lining of the small intestine, it prevents it from absorbing nutrients, such as calcium, that are important for the formation of teeth,” says Dr. Swan. These signs are not enough to confirm celiac disease, so if your dentist is concerned, he will ask you to get tested with your doctor.