Levitt 1982.

Study characteristics
Methods	Randomised, double‐blind, 2‐period cross‐over study
Participants	58 people aged 17‐78 years Tumour types: lung cancer (21 people), ovarian cancer (11 people), breast cancer (10 people), other cancers (16 people) Chemotherapy regimens: combinations of doxorubicin, bleomycin, cisplatinum, cyclophosphamide, dactinomycin, melphalan, mitomycin C, methotrexate, vincristine, etoposide, 5‐fluorouracil. No information on doses reported Chemotherapy emetogenicity: unable to classify
Interventions	Nabilone, n = 58 Placebo, n = 58
Outcomes	Episodes of nausea and vomiting time of assessment unclear, frequency and severity of nausea, withdrawal due to lack of efficacy, adverse effects, episodes of drowsiness
Notes	Dose and duration not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	High risk	36/58 (62%) participants received nabilone, 36/58 (62%) participants received placebo
Selective reporting (reporting bias)	Low risk	Data reported for primary outcome
Other bias	Unclear risk	Assumed washout period sufficient. Unclear if paired analysis was performed. Unclear if groups were balanced at baseline
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Reported as "double‐blind"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding assumed as study reported as "double‐blind"