Two recent studies published in Cell, "Personalized Gut Mucosal Colonization Resistance to Empiric Probiotics Is Associated with Unique Host and Microbiome Features" and "Post-Antibiotic Gut Mucosal Microbiome Reconstitution Is Impaired by Probiotics and Improved by Autologous FMT", have attracted considerable media attention and raise questions and concerns among physicians and patients using probiotics.

Yet:

• Probiotics are generally considered safe for healthy individuals, but the long-term consequences are unknown. For individuals with chronic diseases, immune deficiencies or other risk factors (such as the elderly), patients should seek the advice of physicians to determine if probiotics may be appropriate. In general, probiotics should not be used indiscriminately; potential risks and benefits should be weighed as with all medical interventions.
• This research does not conclude that probiotics are unsafe or useless for everyone. However, the findings suggest that individuals may respond very differently to the same probiotic, depending on their diet, genetics, microbiome and other aspects of health. Experts are trying to better understand which bacteria are best for whom and under what conditions as we move from an era of empirical medicine to an era of precision medicine.
• Probiotics that are currently on the market are foods or supplements. To date, no probiotic products have been approved to treat, mitigate, cure or prevent specific diseases.