Here's what you should be looking for when shopping for a probiotic supplement, according to a doctor.

By Dr. Roshini Raj
March 29, 2018

Not only are there an overwhelming number of probiotic supplements out there, but the labels can be super confusing. You should know that probiotics are classified by genus, species, and strain. The most common genera in products that are geared toward digestive health are Lactobacillus and Bifidobacteria.

Here’s where it gets more complicated: Specific species and strains—the species name comes after the genus, and the strain often looks like a little code of letters and/or numbers on the end—of probiotics have been studied in regards to certain health conditions. For example, Lactobacillus rhamnosus may help ease diarrhea. If you’re lactose intolerant, you might benefit from Lactobacillus acidophilus or Lactobacillus bulgaricus. There’s a wide variety, so it’s wise to check with your doctor to see if one is suited to your needs.

Once you’ve landed on your winning microbe, look at the dosage on the label. In general, the higher the quantity, the better. A dose of anywhere from a billion to 10 billion CFUs, or colony-forming units, per day should do it. Don’t worry about whether your probiotic is refrigerated or not—one kind isn’t superior. And of course, you can also get probiotics by eating fermented foods, like yogurt, kefir, kimchi, and sauerkraut.

Health’s medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine.