Emergency medical treatment (5,3)
I believe the answer is:
first aid
'emergency medical treatment' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for first aid that I've seen before include "'Immediate emergency care (5,3)'" , "Treatment given to injured person before doctor arrives" , "Initial treatment for injured person before doctor arrives" , "medical attention" , "Preliminary medical help pending arrival of doctor" .)