The bad smell which comes could be due to various underlying reasons. It could either be because of inadequate oral hygiene which includes tartar build up around teeth or cavities or any other gum issues. This could also arise from other problems like any ENT issues, any gastric troubles, conditions like
diabetes etc. Kindly visit a dentist to rule out the possible cause.
Health Tips
Good maintenance of oral hygiene which includes brushing twice, flossing twice and use of a mouthwash. Also focus on keep your tongue clean.