Hi, Welcome to health care magic, Abdominal pain,gas trouble and diarrhoea could be due to acute gastroenteritis,viral gastroenteritis,diverticulitis etc. If she is maintaining good diet habit with being dieticians then it is good but here we need to find out the actual cause. She must undergo routine blood count,electrolytes with clinical examination of abdomen or ultrasound of abdomen. She will require antibiotics(quinolones or cephalosporins or antiprotozoals etc.) with antiemetic, antispasmodics and antiinflammatories with prebiotics and probiotics. There might be a need of fluid and electrolyte balance in body. You must consult gastro physician for immediate treatment, Regards,