text: 10 February 2017 Last updated at 09:27 GMT
  Some people are worried hospitals are now getting too busy and overcrowded, meaning patients are having to wait a long time to be seen by a doctor.
  How is this affecting children who get injured and need to go to hospital?
  Jenny went to a children's hospital in Sheffield to speak to a doctor and find out.
  She also meets Lilly and Jake, who have come to hospital needing treatment, to see how their experience went.
target: Winter is a very busy time of year for hospitals, with more people needing to see a doctor.