KEY POINTS 
All probiotics are not the same, and the beneficial effects are strain specific.
Probiotic administration can play an important role in health maintenance and the prevention of disease.
1 Use of multistrain probiotic formulations is likely to be superior to single-strain formulations.
Despite widespread use, reports of side effects related to probiotics have been exceedingly rare.
2 Roman historian Plinio promoted the use of fermented milk for GI infections. In recent decades, increasing attention has focused on the role of probiotics in…