How come some peoples breath stink so much more than others?

Oral hygiene: Breath odor most commonly comes from bacterial colonies in the mouth and teeth. Some people have untreated cavities, and or gingivitis and even open sores in the mouth. "these will contribute to unpleasant breath. They should be active in oral hygiene, seek the help of a dentist and dental hygienist and may need some antibiotic treatments.