Right to avoid first medicinal herb (3)
I believe the answer is:
rue
'herb' is the definition.
(I know that rue is a type of herb)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for rue that I've seen before include "Regret or repent" , "Feel regret for the herb" , "Lament; a herb" , "Repentant sort of shrub?" , "Regret; road (Fr.)" .)