Balm ingredient (4)
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I believe the answer is:
aloe
'balm ingredient' 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 "Flower, maybe vera" , "shrub" , "Fleshy-leaved plant" , "Bitter drug from a leaf juice" , "has a bitter taste" .)