My 7 year old constantly has bad breath despite flossing brushing and mouthwash constantly what can be causing this - she's had issue since 3years old i took her to an ent they saw nothing?

Check lungs: Occasionally bad breath can be caused by something like a lung abscess rather than problems with oral hygeine, nasal or sinus problems. Ask your doctor to test for that if they haven't already done so.

Don't stress it mom: I would check her diet and monitor for a week or so. Bad breath has many causes. Watch her diet for the typical things like onions etc..If it improves great, if not i would see an md specialist for the GI tract if nothing else to relieve your worry. My son is the same age, has excellent home care and his is directly related to diet.

Stomach/GI issues: If your 7 year old has a clean bill of health from your dentist and ent, the next logical place to evaluate for bad breath is further down the digestive track. I would seek out the opinion of your pediatrician about an evaluation for a stomach disorder. Good luck!

Bad breath: I assume Dentist has found no cavities, gum disease, food impaction areas. Has dentist talked to o about the gentle act of tongue scraping? Has diet been evaluated for odoriferous foods? Has she been evaluated for sinus or tonsil problems, respiratory problems, gastro-intestinal problems, or diabetes? You'll have to do some sleuthing to find cause.