Henna and others (4)
I believe the answer is:
dyes
'henna and others' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dyes that I've seen before include "Colours (fabric)" , "Substances for staining or colouring" , "Colouring materials" , "Stains" , "Colour" .)