What commonly leads to bad breath and how should i avoid it?

See your dentist: Sources: gut, plaque (germs), pus (infection), cavities (rotting tooth). See your dentist to find the reason for yours. Until then: avoid foods that cause it (garlic, onions, certain spices); floss and brush your teeth (every night); use listerine (essential oils help), and cut out the sugar habit to minimize further decay (note--i didn't say "eliminate" decay). Xylitol gum is safe between meals.

Gum disease or other: Bad breathe can be caused by untreated gum disease. Other conditions such as gastrointestinal and respiratory problems can be a factor. On occasion, large tonsils can serve as an area where debris, food particles and bacteria can hide. This too can contribute to bad breathe. Consider seeing a dentist to rule out gum disease and then go from there.