Excite by scent (7)
I believe the answer is:
incense
I believe this is a double definition.
'excite' is the first definition.
(thesaurus)
'scent' is the second definition.
(incensing is a kind of scenting)
'by' is the link.
(Other definitions for incense that I've seen before include "It produces a fragrant smell when burned" , "Greatly anger; perfume" , "make you very cross" , "Church perfume" , "Send bananas" .)