Stop all milk products and solids for 24 hours. Clear fluids given by mouth is the most important part of treatment. It may be necessary to give small amounts of fluids frequently, eg a desertspoon every 10 minutes. Babies with gastroenteritis will need about 200 mls per kg body weight in the first 24 hours. If in doubt, give more fluid rather than less, especially if the baby is very thirsty.
Breast feeding can continue during an episode of gastroenteritis.
It is also important to keep a check on temperature. A raised temperature will make a child irritable and cause more fluid loss by evaporation. Give paracetamol and keep the child cool if the temperature is up. Increase, if tolerated, to half strength, then to three quarter strength, and then to full strength milk over two to three days. In older children it may be possible to reintroduce full strength milk after 24 hours, and if this is tolerated, then introduce solids slowly.