Burn balm (4)
I believe the answer is:
aloe
'burn balm' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aloe that I've seen before include "shrub" , "Flower, maybe vera" , "Genus of bitter herbs" , "Succulent plant (4) 5532" , "Succulent plant (may be bitter!)" .)