Hi --I found that foods and drinks containing the many forms of sulfite preservatives in them somehow reacted in my gut and I exhaled hydrogen sulfite (rotten egg gas.) Not much is documented on this percular illness, but I discovered it eventually through trial and error -- wine, beer, dryed fruit, apple cyder, some baked goods, etc etc canned veges, sometimes graps are sprayed with sulfite etc etc its everywhere. all the best -- if this works(it may not be the cause for you) please spread it around to others thanks