Hello lybrate-user, Bad breath
can be due to improper oral hygiene, cold, throat problems, gastric issues etc. First thing to be done is get your mouth and teeth checked and get cleaning and polishing done by a dentist
. Once that is done, maintain oral hygiene by brushing twice a day along with flossing and using mouthwash. Also don't forget to keep the tongue clean. After doing this if the bad breath still persists, then get a thorough body checkup done for any other cause. Thank you.