Table 1

Summary of characteristics of included studies

Study	Design	Age range (years)	Intervention	Comparator	Outcome measure
Ahmadi et al 13	RCT double blind	2–5	Honey	Diphenhydramine	Day time and night time cough frequency and severity (we converted this to a 3 point Likert scale)
Ayazi et al 14	RCT no blinding	1–12	Honey 1; honey 2	Diphenhydramine	Nocturnal cough and sleep difficulty score (validated 5 item, 7 point Likert scale24)
Canciani et al 19	RCT double blind	3–6	Grintuss syrup	Placebo	Day time and night time cough severity (modified from validated questionnaire32)
Cohen et al 20	RCT double blind	1–5	Eucalyptus honey; citrus honey; labiatae honey	Placebo (silan date extract)	Cough score (validated 5 item, 7 point Likert scale24), effect on sleep and combination
Cohen et al 21	RCT single blind	2–5	Grintuss syrup	Carbocysteine syrup	Cough score (validated 5 item, 7 point Likert scale24)
Gupta et al 22	RCT double blind	18–65	Honitus cough syrup	Marketed cough syrup, containing diphenhydramine	Day time and night time cough frequency score (6 point Likert scale), throat irritation
Miceli Sopo et al 18	RCT no blinding	2–14	Wildflower honey+milk	Dextromethorphan; levodropropizine	Cough score (validated 5 item, 7 point Likert scale24)
Nanda et al 23	RCT blinding unclear	>18	Honey+supportive treatments	Supportive treatments only (regarded as placebo)	Subjective symptom score, throat pain recovery, fever recovery
Paul et al 24	RCT partially double blind	2–18	Buckwheat honey	Dextromethorphan; no treatment	Cough score (5 item, 7 point Likert scale)
Pourahmad and Sobhanian25	Single blinded trial	intervention group mean (SD) 24.4 (7.4) comparator group mean (SD) 27.4 (6.2)	Honey+paracetamol, naproxen and chlorpheniramine	Paracetamol, naproxen and chlorpheniramine	Duration of signs and symptoms: rhinitis, muscle pain, fever, throat congestion, cough and sneezing, assessed by investigators
Raeessi et al 26	RCT double blind	21–65	Honey; honey+coffee	Coffee	Cough frequency (questionnaire)
Raeessi et al 15	RCT double blind	21–65	Honey+coffee	Prednisolone; guaifenesin (regarded as placebo)	Cough frequency (questionnaire)
Shadkam et al 16	Four arm RCT no blinding	24–60 months	Honey	Dextromethorphan; diphenhydramine; supportive treatments also suggested to the other groups, including saline nasal drops and paracetamol	Cough score (validated 5 item, 7 point Likert scale24)
Waris et al 17	RCT double blind	1–12	Honey	Salbutamol syrup; placebo (brown coloured sugar syrup)	Cough score (validated 5 item, 7 point Likert scale24)

RCT, randomised controlled trial.