Foul odor is not one mans problem, is a general phenomenon ranging from young to adult, even some animals do have bad odor. So if you are living under the yoke of foul odor, easy and effective bad breath treatments is the only option to wipe out the problem before it disgraces you. By my experience, halitosis comes from different sources, that is why a treatment / drug that works for Mr.A might not work for Mr.B, you can not compare halitosis that comes from eating cloaves to the one cause by bleeding gum or tonsil stone , there are different step to treat them, because they are not from different sources.
The first attack against halitosis is keeping good oral hygiene, brush your teeth and wash your mouth properly. It is even advised that you brush your after every meal to remove hangovers from your teeth because the more they stay in your mouth, the more they pose as dangerous to your breath.
In case if you have sore throat, you can use salt water, after you've scrub and brush your teeth, including your tongue, use warm water to rinse your mouth out, warm salt water is a therapy for sore throat, which is capable of giving you odorous breath. For bleeding gum you can use either lime or lemon, they both have a chemical compound that kills bacteria that cause gum bleeding, be careful with brush when brushing, so that you do not cause more harm than good to your mouth region.
You can also use hydrogen peroxide to rinse you're your mouth before brushing, by doing this you're wiping away bacteria that causes halitosis.
Always consult doctor on dental and breath related issue, as I have said not all foul odor can be treated in the same way because of their diverse causes, seek medical and expert advise, it takes time for me to know this, doctors know more that you think.