There are many microorganisms that can cause diarrhea, including viruses, bacteria, fungi, and protozoa. Your child can pick up viruses, bacteria, or protozoa from other children, or from contaminated food and water. Food poisoning causes diarrhea very quickly. A milk allergy or food sensitivity, which may surface with the introduction of new foods, can also cause diarrhea.

Less common causes of diarrhea include reactions to medication, inflammatory bowel disease, hepatitis, cystic fibrosis, and pancreatitis. An anatomical deformity, such as a fistula, or a congenital defect, such as Hirschsprung's disease or short bowel syndrome, can also cause diarrhea. If your child's diarrhea arises from any of these conditions, she requires medical attention.

Most cases of simple diarrhea are caused by viruses. Viruses invade a child's intestinal tract, causing irritation and inflammation of the intestinal walls. Viruses also induce the cells lining the intestines to secrete fluids. The increase in fluid volume in turn increases peristalsis, the wavelike contractions of the intestines. The result is cramping and the loose, watery, frequent stools characteristic of diarrhea.

Vomiting and stomachache often accompany diarrhea, and abdominal cramps usually come and go, often occurring right before a bowel movement. Depending on the cause of the diarrhea, a fever may or may not be present. When a child is suffering from diarrhea, dehydration is always a serious concern, especially if her temperature is elevated. In the first two or three months of life, an infant can become dehydrated very quickly, so if your newborn develops diarrhea, call your physician.

When to Call the Doctor About Diarrhea In newborns, diarrhea is signaled by an increase in stools, stools that are unusually loose or watery, stools that are yellowish or greenish in color, or stools with a foul odor. You should always consult a doctor about a newborn's diarrhea. If your child experiences severe or persistent abdominal pain with diarrhea, or has blood in the stool, call your doctor right away. If your child has a case of diarrhea that lasts for longer than forty-eight hours, or inter mittens diarrhea that comes and goes over a period of two weeks or longer, seek the ad vice of your health care practitioner. Vomiting that accompanies gastrointestinal upsets should not last for more than twenty four hours. Call your doctor if your child has been experiencing diarrhea with vomiting for longer than that.

Observe your child between episodes of diarrhea to get a sense of how sick she is. If your child is alert and not experiencing cramping between episodes, it's safe to assume her body has the situation under control. But if your child seems weak and the cramping is not relieved between episodes, call your health care provider.

Conventional Treatment
To prevent dehydration, oral electrolyte formulas, such as Pedialyte, Lytren, Ricelyte, and Resol, are commonly recommended for children with diarrhea.