Mark,
I have not heard of this, or experienced problems with patients. In fact, quite the opposite commonly occurs. When people are treated for chronic infections or imbalances (SIBO) they often feel better and don’t get sick as often.
I don’t believe all the bacteria are being killed (good and bad) by antibiotic or botanical intervention. There are trillions of these organisms in the gut. Therefore, what is happening is a reduction in numbers that allows the bowel to reset its normal function.
Dr Woeller