A purgative (5,5)
'a purgative' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for epsom salts that I've seen before include "a purge" , "Purgative" , "They should clear out!" , "Medicinal preparation" , "Medicine taken for heartburn and constipation" .)
'a purgative' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for castor oil that I've seen before include "move furniture quietly?" , "Purgative from African shrub" , "Medicinal stuff" , "A lubricant" , "Some help to clear out inside" .)