Mention about tackling case of migraine causing vomiting (6)
I believe the answer is:
emetic
'causing vomiting' is the definition.
(I've seen this before)
'mention about tackling case of migraine' is the wordplay.
'mention' becomes 'cite' (synonyms).
'about' says the letters should be written in reverse.
'tackling' is an insertion indicator (I've seen this in other clues).
'case of' means to remove the middle letters (outsides of).
'migraine' with its middle taken out is 'me'.
'cite' backwards is 'etic'.
'etic' going around 'me' is 'EMETIC'.
(Other definitions for emetic that I've seen before include "Ipecac is one" , "A medicine to induce nausea" , "Sickening" , "Medicine taken to make one vomit" , "Medicine designed to make one vomit" .)