Medicinal herb for some induced illness (4)
I believe the answer is:
dill
'medicinal herb' is the definition.
(I've seen this before)
'some induced illness' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'DILL' is hidden within 'induced illness'.
'for' acts as a link.
(Other definitions for dill that I've seen before include "Herb of parsley family" , "Pickling herb" , "Culinary herb" , "Herb; rhymes with beak" , "Herb used in pickles" .)