Extremely foul b.O. From stomach? & mild heartburn. Bloodwork/colonoscopy normal. Not hygiene issue. Vitamins/supplmts, colon cleanse didn't work.

Reflux. You may be suffering from gastroesophageal reflux. This is a condition where the stomach acid level is high, causing gas and sometimes even halitosis ( bad breath). Try a trial of over the counter prilosec, 1 tablet every morning before breakfast, and see if you notices difference in 2weeks. Otherwise, seek the advice of a dietician for diet modification and your gastroenterologist.