I have a friend who is a nurse. She works in a doctor's office. They had a patient who came in and said she was having a problem with bad breathe. She had really bad breathe sometimes and she didn't know what was causing the condition. She tried mouthwash, flossing, brushing, chewing gum, mints and some home remedies, but none of them worked to get rid of the odor.
They ran tests at the doctor's office and then the doctor also recommended that she see a dentist. All the tests and the visit to the dentist didn't produce any diagnosis as to the cause of the woman's chronic bad breathe.
She went to an oral specialist, and it was eventually determined that when she ate, food was getting trapped in her mouth. And the primary place where the food was getting lodged was in the piriform sinus. And of course, when food gets stuck in your mouth, bacteria starts to attack the bits of food and this cause a foul odor.