Sack of medicine with a covering of gauze (7)
I believe the answer is:
pillage
'sack' is the definition.
(I've seen this in another clue)
'medicine with a covering of gauze' is the wordplay.
'medicine' becomes 'pill' (pill is a kind of medicine).
'with' says to put letters next to each other.
'covering of' means to remove the middle letters (only the letters which cover the word).
'gauze' with its centre removed is 'ge'.
'pill'+'a'+'ge'='PILLAGE'
'of' acts as a link.
(Other definitions for pillage that I've seen before include "Loot" , "Rob with violence" , "Sacking" , "Violent stealing" , "Plunder, sack" .)