It can be difficult to tell when a baby or toddler is seriously ill, but the main thing is to trust your instincts.
You know better than anyone else what your child is usually like, so you'll know when something is seriously wrong.
Here's a checklist of warning signs that might indicate your baby or toddler is seriously ill and requires medical help.
Find out more about high temperature (fever) in children and what to do
If your child has any of signs of serious illness, get medical help as soon as possible:
Call 999 for an ambulance if your child:
Trust your instincts. You know what's different or worrying behaviour in your child.
Learn the signs of serious illnesses that can affect children, including: