In order to restore harmony in your gut, you may have to do a little detective work (and perhaps see a gastroenterologist) to get to the root of the problem. If you have a food intolerance, for instance, you'll need to remove offending food from your diet. For slow motility, your doctor might advise you to eat small amounts more often throughout the day and load up on fiber. If you have SIBO, you'll need antibiotics.
Most people, however, don't have any of these issues, despite having cramping, bloating, and irregular bowel habits. If that sounds like you—or you just suffered through a stomach virus or are taking antibiotics for another ailment—you may need to work to repair your internal ecosystem. The fix: probiotics.
Probiotics are good bacteria that are naturally found in foods like yogurt (assuming it contains "live active cultures") and kimchi, a traditional Korean side dish made from fermented cabbage and other vegetables. Kefir, sauerkraut, and miso soup are good sources, too.
You can try eating these foods more often and see if it makes a difference, says Dr. Cheung, but a better bet once you already have a problem may be to start taking a probiotic supplement.
There are loads of probiotic supplements on the market, but they're not all created equal. Two key factors to consider when making your choice are survivability and the specific bacterial strain.
In order for a probiotic to help you, it has to be able to bypass your stomach. The stomach is very acidic, and it will wipe out most bacteria (including good ones). To make sure a probiotic reaches your intestines, choose one that has a protective coating.
You should also know that probiotics contain different strains, and there's more research to back up certain ones. The best-studied ones are lactobacillus and saccharomyces (it's actually a type of yeast).
Probiotics aren't a cure-all, and they'll only help you if your initial problem was a lack of good bacteria. Dr. Cheung's advice: Try them for a month, and if you still don't feel better, it's time to see (or revisit) your doctor.