Sickness and diarrhoea bugs are caught easily and are often passed on in places where there are lots of children.
Feeling sick and suddenly being sick are normally the first signs. Diarrhoea can follow afterwards. If your child is not vomiting frequently, is reasonably comfortable in between and you are able to give them frequent small amounts of water, they are less likely to become dehydrated and probably don't need to see a doctor. Speak to your GP if they are unwell for longer than 24 hours or sooner if they are newborn or if you notice signs of dehydration.
If you're breastfeeding, keep on doing so even more frequently. Offer older children plenty of water, or an ice-lolly for them to suck. If they want to eat, give them plain foods like pasta or boiled rice (nothing too rich or salty).
Keep them away from others, especially children, who may pick up infection. Be extra careful with everyone’s handwashing.