Dehydration is perhaps the most common complication of diarrhea. It occurs because fluids and salts pass through your body too quickly to be absorbed by the intestine. Dehydration can be serious, especially in children and older adults. Sometimes an IV is needed to restore a healthy balance in the body.
High fever and bloody stools are other potential complications, and require medical attention. Be sure to call your doctor if you notice anything unusual or persistent.