Vomiting and diarrhea are frequently encountered in pediatric patients. Dehydration, a serious consequence of both vomiting and diarrhea, results in the deaths of more than 700 children annually in the United States. With appropriate parent education, both morbidity and mortality can be reduced, and much of the anxiety about these problems can be alleviated. Parents must be educated to recognize the associated signs and symptoms that indicate serious disease and warrant notifying the physician. Fluid therapy should be individualized, and parents should be informed of the appropriate steps to take. Parents must make quantitative observations and keep records not only to enable the physician to assess adequate fluid balance but also to be able to demonstrate to themselves the effectiveness of the treatment. It is just as important for the physician to reassure parents, who will have concerns about long-term nutritional or growth consequences.