It's bacteria. Have your dentist scale/root plane your teeth and give you some antibiotics to get rid of the bacteria. Then use antimicrobial rinse and toothpaste along with a tongue scraper to maintain. That's what I'm doing now. It's costly but the cost of a funeral would be far more. My old dentist kept telling me there is nothing wrong with my teeth. I know there was nothing wrong with my teeth it's my breath that was the problem. I'm 35 and the dentist told me I have the teeth of a 24 year old. Fine and dandy, but help me with the problem I came here for. Sometimes you really have to tell them what you need. Run floss between your teeth and smell it. Scrap your tongue and smell it. where is the odor coming from?