Sunburn soother (4)
I believe the answer is:
aloe
'sunburn soother' 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" , "Bitter drug from a leaf juice" , "Succulent plant (may be bitter!)" , "has a bitter taste" , "Bitter fruit" .)