It's sort of the opposite of a probiotic. In many organisms, including many non-human mammals, it short-circuits normal metabolic processes. Xylitol-sweetened products will easily sicken, and frequently kill cats and dogs, for instance.
> Conclusions: The results suggest that chewing gum with xylitol or sorbitol/maltitol can reduce the amount of dental plaque and acid production in saliva in schoolchildren, but only the xylitol-containing gum may also interfere with the microbial composition.
There are Xylitol sprays also, advertised for moisturizing a dry mouth. Spray, swish, and spit it out and little will reach your intestinal microbiome. Best done right before a time when you won't be eating or drinking so the residue has some time to act on the bacteria on the teeth (e.g., right before a shower or before bed).
