I'm 45 years old. my teeth and gums are in great condition. i brush, floss, and scrap my tongue. however, i still have chronic bad breath. i've got blood tests done but nothing came out. what should i do?

Monitor : Lets attack this from several angles: increase brushing to 5 minutes one time per day behind last teeth, tops, cheek and tongue sides & floss first. You can brush more than once per day but one time needs to be for 5 min. Now monitor your diet. Cut out the usual suspects for 10 days (onion, garlic, pizza, thai food, smoking, coffee on an empty stomach..) and see how you do.

Tonsils: Do you still have your tonsils? If yes, do you see white stone/plaques in them? If you do, this where you problem lies. But could be many other issues. An ENT visit will might provide insight.

Bad breath: When was thelastrimeyou saw a dentist and hadyourteeth cleaned? Good brushing and flossing alone is not the only answer. Untreated periodontal and decY can cause bad breath. OnthercUsescan be sinus, diabetes, acid reflux,another metabolic diseases can also be a cause. So working with your dentist and physician together will help you get the answer.