Hi ! I am so sorry your mother has to go through this side effects after taking antibiotics. I have had mouth infections after radiation therapy for mouth cancer. So, I have had to take antibiotics quite often to fight this infections. One of the side effects could be loose stomach or constipation, that could last up to six months after taking the antibiotic. So her doctor is right: it will take care of itself with time. Just eat healthy and be patient. Lots of raw apples, I guess! Best wishes, Loli