Long-term digestive issues including acidity, constipation, poor digestion, or disorders like reflux or irritable bowel syndrome (IBS) may be the cause of your symptoms. Gas, acidity, constipation, gum disease, and stomach infections can all cause bad breath. Eat meals on time, drink more water, stay away from junk, greasy, spicy, and late-night foods, and increase your intake of fruits, vegetables, and whole grains to increase your fibre intake. Digestion and bowel movements can also be aided by regular activity and restful sleep. You may talk to a doctor about probiotics or medications like pantoprazole for acidity, but since this has been going on for a long time, it's crucial to see a gastroenterologist for appropriate tests like stool testing, acidity/reflux assessment, or screening for infections like H. pylori. Additionally, see a dentist once to rule out dental or gum disease.