Hello --
You need to be tested for possible celiac disease, an intolerance for gluten in the diet. One of the cardinal symptoms of this is foul-smelling stool, along with
diarrhea, greasy-looking or fatty stool, bloating and vague general abdominal discomfort. This would all seem to fit with your complaint, and while there is no cure, it can be managed very well by diet changes alone.
I hope this is helpful to you. Good luck with this and please follow up with us as needed.