Eradicate boil as treated by hospital (7)
I believe the answer is:
abolish
'eradicate' is the definition.
(I've seen this in another clue)
'boil as treated by hospital' is the wordplay.
'treated' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'hospital' becomes 'H' (abbreviation for hospital on maps).
'boil'+'as'='boilas'
'boilas' is an anagram of 'abolis'.
'abolis'+'h'='ABOLISH'
(Other definitions for abolish that I've seen before include "Put an end to (practice)" , "Put an end to, formally" , "delete" , "Do away with, rescind" , "Formally do away with" .)