Racecourse salts? (5)
I believe the answer is:
epsom
I believe this clue is a double definition.
'racecourse' is the first definition.
(I've seen this before)
'salts?' is the second definition.
(as in Epsom salts)
(Other definitions for epsom that I've seen before include "Derby town" , "Home to the Derby and the Oakes" , "can have horses" , "Poems about English Derby venue" , "Surrey racecourse" .)