Halitosis is a common condition often caused by a build up of bacteria in the mouth because of gum diseases, food or plaque, lack of good dental hygiene etc
Causes
1)use of alcohol related products
2) certain food
4) lack of good dental hygiene
5)some certain drugs
6)mouth, nose and throat infection
7) diseases etc
How do I know I have halitosis
2) when you notice bad breath from your mouth even after brushing or flossing
2)when people tell you about you having a bad breath
And other ways
Treatment
1) visit a dentist to know what the problem is
2) practice good dental hygiene
3)use of home remedies
4) use of mouth wash
5)use of toothpaste that helps cure odour etc