Heya! Okay - heres some hope - my bro had exactly same problem and is currently totally cured standing of 2 years now! ALl he did - was change his diet SEVERLY! He basically had really bad diarreah (which is basically chronic constipation...ie none of the food was coming out - just water...and that meant food was literally rotting inside him) so think first do you have chronic diarreah or constipation?
He cured it in 2 weeks by going on the Gillian Mckeith Diet, just by chance, because I went on it - but don't worry - he didn't follow it fully, its just that I was cooking. Basically he just upped his fibre content by a million! No juke, crisps...etc, and eat a lot of fruit, had porridge for breakfast (with soya milk - he liked it!!??) had rice and lentils and vegetables for his main meals.
If you have any other questions about his specific diet post whatever you want!
Anyway, he is cured and is holidaying with his girlfriend as I write! You have a symptom of something else...NOT A DISEASE! Probably the food is just sitting inside you - think about what happens when you leave food in a bin for too long - it rots, and stinks up the place...no matter how you try and disguise it - air freshners, etc! You have to change the bin, i.e. clean your insides, and a really high fibre diet can be the way to achieve this! ALso, he cut out all dairy products (hes vegetarian anyway!) and meat - but has reintroduced dairy again after a month or so with no problem! If he eats TOO much dairy he gets bad breath again, and begins to get BO...basically because dairy rots faster!