Hi.. Thanks for the query.. Bad breath can occur due to a number of causes other then dental or digestive causes like sinus infections, tonsil stones, post nasal drip, poor oral hygiene and excessive regular intake of onion and garlic.. You should consult an Oral Physician and get evaluated.. As of now start chewing flavoured sugar free chewing gum, it can be mint or menthol flavoured.. Gargle with flavoured antiseptic mouthwash.. Limit intake of high aroma foods like onion and garlic.. Maintain a meticulous oral hygiene.. Eat plenty of probiotics like Yogurt.. Drink plenty of water.. Hope this helps. Regards.