NEW YORK, N.Y. (WPVI) -- From yogurt to juices, it seems every food & supplement is labeled as "probiotic" now.
Over the past 5 years, sales have increased 30 per cent, making probiotics a $30 billion dollar a year global business.
And they claim to do everything from improve digestion to help you lose weight.
These combinations of bacteria and yeasts are a very hot topic of study now.
"Probiotics have shown some evidence for bloating, intestinal infections, gut irregularity, and there are other things being studied," says Dr. Mark Pochapin, of N.Y.U./Langone Medical Center.
Experts say they may help by creating a barrier against bad bacteria in the gut, though doctors aren't exactly sure how.
But experts say probiotics don't have a lot of solid science behind them yet.
"It could be for weight loss, it could be for boosting your immune system, it could be not getting sick, but we're certainly not there yet," says Dr. Pochapin.
Researchers have a host of studies underway right now.