I have had this problem for over 10 yrs now. Sometimes my stomach passes out a stronge foul gas like sewage,the frightening thing is it comes out on it's own without me feeling it or having the urge to pass any wind.I empty my bowels daily, i have had stool and blood test done doctors found nothing wrong, i've also been priscribed antibiotics for a bacteria called Giardia that did not help I have no idea what's wrong please help

I am sorry I cant offer you any advice or answers, but thought I would let you know that I suffer pretty much the same thing. So if nothing else I can at least send you my empathy.
one thing I have noticed though is it seems worse if I chew gum alot. i think I may be swallowing too much air when I chew or it may be upsetting my stomach acids.
My kids call me horrible names and throw cushions at me lol

I think you are not eating enough green leafy veggies. The chlorophyll in these veggies act like a deodorant.
I works for -- I also use a product called Green Phyters by the Vitamin Shoppe.
It contains several greens in a tablet form.

I Wish you well~~~Harry