Boselli 1972.

Study characteristics
Methods	Double blind randomised controlled trial
Participants	Stage 1 of study (n = 31): malignant neoplasms (including GI, renal, hepatic, pulmonary neoplasms or pleural cancer n = 12) Stage 2 of study (n = 40): various respiratory disorders (e.g. spontaneous pneumothorax, asthma, chronic bronchitis, and lung neoplasms n = 12) Unknown age and gender characteristics
Interventions	Intervention drug (cancer patients n = 6): 1‐N‐fenil‐4‐N‐(2,3‐diidrossipropil)‐dietilendiamina (hydropropizine) Control drug (cancer patients n = 6): oxadiazol Both solutions were prepared with identical characteristics, put in identical bottles, only identifiable by differing initials. Codes were not revealed until after the experiment was completed. No information on drug dosage
Outcomes	Pre‐treatment: in patients where coughing fits were particularly intense, the cough had a ‘non‐productive’ character which seriously impacted upon rest (n = unknown) Post‐treatment: Intervention drug group: 4/6 = excellent (80% to 100% reduction in coughing fits); 1/6 = good (60% to 80% reduction in coughing fits); 1/6 = moderate (40% to 60% reduction in coughing fits) Control drug group: 1/6 = good; 3/6 = moderate; 2/6 = none (less than 40% reduction in coughing fits) Jadad score = 3
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details provided
Allocation concealment (selection bias)	Unclear risk	No details provided
Blinding of participants and personnel (performance bias) All outcomes	Low risk	“Both solutions were prepared with identical characteristics, put in identical bottles, only identifiable by different initials. Codes not revealed until after experiment finished.”
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information provided
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No dropouts reported
Selective reporting (reporting bias)	Low risk	All expected outcomes listed in the section on “Methods” were reported
Other bias	Unclear risk	Insufficient information provided
Size of study	High risk	Small sample size (31 in stage 1 of study, and 40 in stage 2 of study)