Healing plant (4)
I believe the answer is:
aloe
'healing plant' 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 "O, ale with bitter plant" , "Bitter fruit" , "Fleshy-leaved plant" , "Flower, maybe vera" , "Succulent plant (may be bitter!)" .)