Hi! Welcome to Healthcaremagic! I read your query. Bad breath can be due to local oral causes or as a result of systemic causes. If your mouth is clean, look for other symptoms. Dry mouth for long durations, Diabetes, high carbohydrate diet, Gastrointestinal disease, Lung disease, liver, kidney, blood, all can lead to bad breath. I suggest you to meet a physician and give history and get check up done. Do you have any medical problem? Any acid reflux or acidity? Get LFT, KFT, chest xray, ENT check up and blood test done. After confirmation of any underlying disease, it needs to be cured. Besides that, maintain good oral hygiene. Use mouthwash. Drink lots of fluids and avoid dry mouth. Chew sugarless gums. Massage gums with gum paint. Have healthy diet with multivitamins and minerals. Follow up regularly for oral prophylaxis. At times even after cure of bad breath, patient has a feeling of bad breath. Its psychogenic. Rule this out with the help of dental check up. Hope the answer helps you. Thank you!