Salt thrown in for each dressing (7)
I believe the answer is:
plaster
'dressing' is the definition.
(plaster is a type of medical dressing)
'salt thrown in for each' is the wordplay.
'thrown' is an anagram indicator.
'in' means one lot of letters goes inside another.
'for each' becomes 'per' (per person).
'salt' with letters rearranged gives 'last'.
'last' put into 'per' is 'PLASTER'.
(Other definitions for plaster that I've seen before include "Adhesive material" , "First-aid item" , "Substance for coating walls" , "Cover for cut" , "____ of Paris" .)