Plant used first of all in astringent lotions or embrocations (4)
I believe the answer is:
aloe
'plant' is the definition.
The answer is an example.
'first of all in astringent lotions or embrocations' is the wordplay.
'first of all in' says to take the initial letters.
The first letters of 'astringent lotions or embrocations' is 'ALOE'.
'used' is the link.
(Other definitions for aloe that I've seen before include "Bitter drug from a leaf juice" , "shrub" , "has a bitter taste" , "O, ale with bitter plant" , "Fleshy-leaved plant" .)