Vomiting and diarrhea usually result from gastroenteritis (GE), an intestinal infection. They can also arise from acute food poisoning, food allergies, or surgical problems such as appendicitis. All GE may be accompanied by a vague, crampy pain especially right before an episode of vomiting or diarrhea. Surgical problems always have a more constant, sharp, localized pain- severe enough to make the child tense up when you try to touch his/her belly. You should call immediately if your child is experiencing this type of pain.
Only a tiny percent of GE cases require any medication at all to get better. Those few who MAY need an antibiotic will be distinguished by a high fever >104, bloody stools, persistent diarrhea for more than 3 days. We will want to culture the stool of a child with this pattern, but stool tests are not routinely necessary in children with diarrhea.
The main danger of GE is dehydration- not enough fluid in the body. As long as you can keep up with replacing fluids being lost, however, the child will be fine. This is easier to do with diarrhea than it is with vomiting. Signs of dehydration include decreased frequency/amount of urine, dark/strong smelling urine, sunken eyes and/or soft spot, extreme drowsiness or fussiness, crying without tears, and dry/sticky mouth. Dehydration is best prevented and treated by giving small amounts of liquids very frequently. The best liquid to give by far is an oral electrolyte or rehydration solution (Pedialyte). If you feel like your child is becoming dehydrated despite your best efforts you should not hesitate to call. For a child with milder symptoms other clear liquids can be used such as juice (any kind except apple), flat soda, or sports drinks (Gatorade).
When diarrhea is the main problem, and there is little or no vomiting, you should continue to feed your child foods. Despite the GE he or she still needs and is able to absorb the calories. Diarrhea actually gets better faster is there is solid matter in the intestine to form normal stools. Foods to avoid because they could make matters worse include milk, cheese, and most other diary products, fast food, fried foods, and foods that are particularly spicy. Foods that are often quite good for a child with GE symptoms are cereals, toast, crackers, rice, pasta, potatoes, and yogurts. Diarrhea medicines, over the counter prescriptions, are rarely indicated. Some of them are actually very dangerous. The key to managing your child with vomiting and diarrhea is FLUIDS, not medicine.