George 1983.

Study characteristics
Methods	Randomized double‐blind 2‐period cross‐over study
Participants	20 people, mean age 54.1 years Tumour type: advanced gynaecological cancer who vomited during the first chemotherapy treatment Chemotherapy regimen: cis‐platinum (50 mg/m2) with hydration. Vomited during the first treatment. Doxorubicin (40 mg/m2), cyclophosphamide (600 mg/m2) and cis‐platinum (11 people); cyclophosphamide 600 mg and cis‐platinum (3 people); cis‐platinum (6 people) Chemotherapy emetogenicity: high
Interventions	Nabilone 1 mg 24 hours before chemotherapy then 1 mg 3 times daily orally Chlorpromazine 12.5 mg IM before chemotherapy with additional dose if requested
Outcomes	Number of vomiting episodes in 24 hours, participant preference, adverse events
Notes	Translated from French
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomly allocated by lottery
Allocation concealment (selection bias)	Low risk	Identical placebo
Incomplete outcome data (attrition bias) All outcomes	Low risk	All people were included in the analysis
Selective reporting (reporting bias)	Low risk	Data reported for primary outcome
Other bias	Low risk	There was no evident difference caused by the order of administration of the drugs
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Identical placebo, double‐dummy tablets used
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding assumed as study reported as double‐blind