Sickness in Ghana? Use antibiotics (6)
I believe the answer is:
nausea
'sickness' is the definition.
('nausea' can be a synonym of 'sickness')
'in ghana? use antibiotics' is the wordplay.
'in' indicates a hidden word.
'NAUSEA' is hidden within 'ghana use antibiotics'.
(Other definitions for nausea that I've seen before include "Sickness, biliousness" , "Feeling of imminent sickness or upset stomach" , "Queasy feeling" , "Sensation of queasiness" , "Unpleasant feeling" .)