I ve had IBS with more or less chronic diarrhea for a really long time. I m 58, six feet tall, and have never weighed more than 120 pounds in my whole life. Sometimes the IBS is so intense and painful that it nauseates me and leads to vomiting. Yesterday I vomited three times a very thick and dark emesis unlike any I d ever experienced. Because I wasn t feeling well, I had the bathroom light off, and I was too disgusted and afraid to take a good look at it. I figured it was some chocolate cookies I d had, but that had been almost three hours earlier. Usually the nausea passes but today it hasn t and I can t eat. But I have trouble with appetite under the best of circumstances.