Mouth odor is not at all a normal thing. First you need to look for the causes of mouth odor. Few of the common ones are:

1. Dry mouth
2. Poor oral hygiene
3. Stress
4. Carious teeth
5. Tonsils
6. Certain food products

After knowing the cause you can confidently go for a specific treatment. Few of the treatment options are

1. Never allowing your mouth to get dry
2. chewing a mint gum
3. Change in the diet
4. Brushing properly as given in the link....http://www.identalhub.com/article_why-do-we-need-to-brush-our-teeth-156.aspx
5. Green Tea and cloves are also helpful 

For more info you can visit the link....http://www.identalhub.com/articlecategory-bad-breath-6.aspx