Kötü bir nefes genellikle oral şartları ilgilendiren bir durumdur. Milyonlarca insan için tuhaf ve utanç verici olan bu durum, tıbbi veya dental sorundan ABSTRACTBad breath (Halitosis, oral malodor) people commonly encounter, which is a condition that negatively affect social relationships in all over the world. Due to importance of social environment in nowadays, the psychological trauma caused by halitosis will be so stronger on the individuals. This situation has lead individuals to seek treatment.This article offers the definition, odor of formation, etiology, classification of halitosis and approach that includes methods of measurement.