I have taken Rifaximin many times. I occasionally get a condition called SIBO (small intestine bacterial overgrowth) which is a result of my gastroparesis. The antibiotic works only in the GI track, and very little enters the blood stream. It is also used for travelers diarrhea, IBS (with chronic diarrhea), and hepatic encephalopathy.

It is a very expensive antibiotic and often insurance won't pay for it...unless the doctor well documents certain conditions.

All medications (as far as I know) have 'other ingredients', so I'm not sure what your question is. Why are you being prescribed it?