What is cause of bad breath ?
May be also a sign of metabolic syndrome ( check fishy odor )
Depends on the underlying cause !
and what is its treatment?
Halitosis i,e bad breath may be due to oral causes i,e dental caries , priodontal diseases, ulcers etc or may be due to ENT cause i,e pharyngitis, tonsilitis etc or may be due git cause i,e hiatal hernia ,reflux esophagitis etc