Protection from decay and drugs surrounding one (4,4)
I believe the answer is:
riot gear
'protection' is the definition.
'decay and drugs surrounding one' is the wordplay.
'decay' becomes 'rot' (rot is a kind of decay).
'and' says to put letters next to each other.
'drugs' becomes 'gear' (I have seen 'illegal drugs' mean 'gear' so perhaps 'drugs' could also mean 'gear').
'surrounding' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'rot'+'gear'='rotgear'
'rotgear' enclosing 'i' is 'RIOT GEAR'.
'from' is the link.
(Other definitions for riot gear that I've seen before include "Clobber with truncheon maybe" , "It's worn by police" , "What police use to control" , "protective clothing" .)