I took probiotics, ate yoghurt for the first 10 year of having ME. There were no stomach symptoms with the disease for me for the first year or so. After that I started vomiting, could not digest foods I had commonly eaten before, had constipation and had a distended bloated stomach. The probiotics helped with these all but especially with the last part. Although it sounds horrible, the stomach problems were only a minor part of ME for me when compared to the viral symptoms and the PEM.