Men hid pain's effects with painkiller? (6,4)
I believe the answer is:
indian hemp
'painkiller?' is the definition.
'men hid pain's effects' is the wordplay.
'effects' indicates anagramming the letters.
'men'+'hid'+'pain'='menhidpain'
'menhidpain' with letters rearranged gives 'INDIAN HEMP'.
'with' acts as a link.
(Other definitions for indian hemp that I've seen before include "Pot plant" , "cannabis supplier" , "used as source of drugs" , "familiar to ropemaker?" .)