A five-year-old girl is fighting for life in hospital after a possible methadone overdose in Sydney's north-west.
Police were called to a home at Quakers Hill on Tuesday at 2pm after she was found unconscious.
It is understood the girl was in the care of a relative, who tried to wake her and found her barely breathing.
The child was airlifted to Westmead Children's Hospital where she remained on Wednesday in a critical condition.
Police are investigating whether the girl ingested the drug methadone.
The Child Abuse Squad is investigating.
