Whoa!!! Let’s slow down the probiotic wagon train!
1) Researchers began by giving probiotics to germ-free mice, in which they were actually able to induce the desired microbial changes. When they gave the probiotics to mice that were already colonized with their own innate bacteria, however, there were evident resistance patterns. They were not able to induce the colonization that they thought they would when they gave the probiotic. The same effect was evident when they tested it in humans. There seems to be certain bacterial resistant patterns in hosts that either facilitate or block the colonization intended by this probiotic effect.
2) Researchers found that there was a rapid reconstitution of the normal biome when they gave the patients their pre-antibiotic stool back. Comparatively, the use of probiotics was associated with a marked delay in patients being able to return to what their normal microbiome was before antibiotics.
3) Nearly a third or more of all trials included reported no adverse event monitoring or harm, whereas 98% provided no adequate documentation, validation, or standardization in reporting adverse events or serious adverse events. Given the high variability in the quality of existing data, the authors concluded that it may be too premature to make any broad conclusions about the safety of these interventions.
Certainly, just like any other medication, potential harm needs to be assessed in probiotics.
Source: The Probiotics Trend: Should We Be All In or Call Time Out?