Hodge 2014.

Methods	2‐group RCT comparing commercial aromatherapy preparation to placebo
Participants	94 adult surgical patients (54 treatment/40 control) patients with planned admission. Patients with an allergy to lavender, peppermint, spearmint, or ginger excluded. Mean Age = 41.25 years. SD = 14.2. Range= 18‐86 Setting: military medical centre, USA
Interventions	Treatment: patient‐administered inhalations from 'QueaseEase™' commercial aromatherapy inhaler containing peppermint, spearmint, lavender and ginger oils. Control: unscented placebo inhaler. On first complaint of nausea, "the patient is instructed to remove the cap, hold the container under the nose, and take a few deep breaths."
Outcomes	Nausea severity at initial report and 3 min as measured on a 10‐point Likert scale (0 = no nausea, 10 = worst possible nausea). Patient satisfaction as measured by a questionnaire.
Notes	27 patients eligible for the study did not receive the allocated treatment. Additional information requested & supplied. QueaseEase™ devices and placebo devices were provided free of charge by the manufacturer.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Probably done: further information received from study author, Nancy Hodge, states that a computer‐generated random number sequence was used.
Allocation concealment (selection bias)	High risk	Comment: probably not done. No concealment described in published paper or extra information provided by study author
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Probably done: further information from study author, Nancy Hodge, states: "The perceived nausea VAS forms and interview questions forms were placed in a sealed packet along with either an aromatherapy inhaler or a placebo inhaler. Each packet was numbered and randomly assigned an inhaler. The sealed packets were placed on the nursing unit and when a post‐op patient complained of nausea the nurse took the next numbered packet to the bedside." Comment: despite these measures, unblinding of participants would have occurred on opening the packets due to the scent of the aromatherapy product
Blinding of outcome assessment (detection bias) All outcomes	High risk	Comment: despite the above measures, unblinding of nursing staff would have occurred on opening the packets due to the scent of the aromatherapy product. The nursing staff who administered the intervention also measured the outcomes.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: the 27 patients whose outcomes were not included did not receive any of the study treatments
Selective reporting (reporting bias)	Low risk	Comment: no evidence of selective reporting. All stated outcomes reported
Other bias	Low risk	Comment: no other sources of bias apparent