It is not that specific foods clear up the diarrhea but rather that you should avoid foods that make it worse. For example, for a few days or a week after a bad bout, the lining of the intestine may have lost the surface cells that provide lactase, an enzyme that helps digest milk. For this reason, your child may be temporarily lactose intolerant. She may tolerate rice milk better than regular milk.
Another problem may be the loss of normal, or "good," bacteria in the bowel. You can help replace these bacteria by feeding her yogurt that contains active culture (the milk in yogurt is changed enough that children can usually tolerate it) or by giving her a dose of so-called probiotics such as acidophilus or bifidus, available as granules that you can sprinkle on soft food.
Loose stools can persist for a while after the initial infection is over. Persistent diarrhea can irritate skin in the diaper area, creating redness and sometimes open sores. Washing with soap and water after every loose stool and protecting and soothing the skin with an ointment can prevent or minimize the risk.
