Irritable bowel syndrome (IBS) sometimes accompanies fibromyalgia. If patients have frequent gastric upset -- such as constipation, diarrhea, painful gas or abdominal bloating -- they should ask their physician whether they could be suffering from IBS. They should also learn to avoid the foods and habits that trigger their symptoms. High-fat foods, caffeine, and alcohol often are culprits. At the same time, upping their intake of high-fiber foods may help these and other fibro symptoms.