A new University of Wisconsin study suggests using menthol cough drops excessively can worsen a cough.  The report is published this month in the Journal of the American Board of Family Medicine.  U-W researchers surveyed 550 patients and found that for most of them too many cough drops – especially menthol – made coughs more severe.  The study also showed the cough lasted 12-and-a-half days for cough drop users and nine-point-eight days for non-users.