There are many different reasons for having halitosis and many different remedies. Often it can be caused by diet/nutrition and/or medication. Here are a couple of nutrition tips to help you try to deal with it. These are a couple of natural foods that may provide some relief for bad breath.
1.    Plain yogurt helps the levels of hydrogen sulphide in the mouth, lowering the levels
2.    Berries prevent mouth bacteria
3.    Chew on mint (real mint) or Parsley, they release oils to help combat bad breath
4.    Cinnamon
5.    Try nibbling on a mixture of Anise, Cardamom, Coriander and Fennel Seeds.
6.    Try to convert part of your diet into eating raw fruit and veg. Especially things like Apples and Carrots, the high fibre content and the increased level of saliva the mouth produces when eating them is like a home made mouth wash.
7.    Lemon can neutralise the bad smell, try small bites of lemon rind and if you can stand it suck the juice from a lemon slice!
Hope these help some. If you have any tips please feel free to post them.