1. For two to four weeks, stop eating the most common irritation culprits: soy, dairy, citrus, wheat, and nuts. You can also try eliminating other foods that you eat frequently or tend to crave. These may cause IBS symptoms, too, according to Benjamin Kligler, MD, MPH.
   
   
2. If symptoms don't improve during the elimination period, you may not have a dietary IBS trigger. If you find relief, challenge yourself by reintroducing one food at a time for three to four days, noting how your body reacts. If you suffer a bout of IBS, take the food back out. If you feel fine, leave the food in your diet. Then progress to the next test food.
   
   
3. Assessing all five ingredients takes about two months, and by the end, you will likely have identified food categories you're better off avoiding. “It's not a cure,” says Kligler, “but it can give you a greater degree of control over your symptoms. If dairy is a big trigger, it doesn't mean you can't ever eat it. But you know that if you eat cheese fondue, you're going to experience symptoms for the next few days.”

For more about how probiotics can aid digestion, read Get Cultured.