I. Paul, J. Beiler, A. McMonagle, M. Shaffer, L. Duda and C. Berlin. Effect of honey, dextromethorphan, and no treatment on nocturnal cough and sleep quality for coughing children and their parents. Arch Pediatr Adolesc Med. 161(12)1140-6. PMID: 18056558
This study compared honey, an allopathic remedy and no treatment, for symptomatic relief of nocturnal cough and sleep difficulty due to upper respiratory tract infection. Parents rated honey as the superior treatment.
M. A. Raeessi, J. Aslani, N. Raeessi, H. Gharaie, A. A. Karimi Zarchi and F. Raeessi. Honey plus coffee versus systemic steroid in the treatment of persistent post-infectious cough: a randomised controlled trial. Prim Care Respir J 22(3)325-30.
This study concluded that a combination of honey and coffee can be used as treatment of a cough that persists after a common cold or an upper respiratory tract infection. It had better results than treatment with systemic steroids. Coughing can remain for more than three weeks or perhaps for many months.