European friend keeping very good herbal remedy (9)
I believe the answer is:
echinacea
'herbal remedy' is the definition.
(I've seen this before)
'european friend keeping very good' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'friend' becomes 'china' (cockney rhyming slang, mate is china plate).
'keeping' indicates putting letters inside.
'very good' becomes 'ace' (I've seen this before).
'china' enclosing 'ace' is 'chinacea'.
'e'+'chinacea'='ECHINACEA'
(Other definitions for echinacea that I've seen before include "Herb" , "Plant of the daisy family used as a herbal remedy" .)