> Probiotic bacteria readily colonised the gut of everyone in the second group after antibiotics had cleared the way. However, the researchers were surprised to find that this prevented the return of the person’s normal microbiome for up to six months. “The probiotics very potently and persistently prevented the original microbiome returning to its original situation,” says Elinav. “This was very surprising and alarming to us. This adverse effect has not been described to date.”

That was the part I found interesting.