| Study | Reason for exclusion |
|---|---|
| Adib‐Hajbaghery, 2015 | Prevention of PONV, not treatment |
| Apariman 2006 | Prevention of PONV, not treatment |
| Apfel 2001 | Not RCT/CCT. Not aromatherapy |
| Arfeen 1995 | Prevention of PONV, not treatment |
| Betz 2005 | Not RCT/CCT |
| Bone 1990 | Prevention of PONV, not treatment |
| Briggs, 2016 | Not RCT/CCT |
| Buckle 1999 | Not RCT/CCT |
| Chaiyakunapruk 2006 | Prevention of PONV, not treatment |
| Chiravalle 2005 | Not RCT/CCT |
| Chrubasik 2005 | Not RCT/CCT |
| Couture 2006 | Prevention of PONV, not treatment |
| Dabaghzadeh, 2014 | Prevention of PONV, not treatment |
| de Pradier 2006 | Not RCT/CCT |
| Eberhart 2003 | Prevention of PONV, not treatment |
| Eberhart 2006 | Not RCT/CCT |
| Ekenberg 2007 | Not RCT/CCT |
| Ernst 2000 | Not RCT/CCT |
| Fujii 2008 | Not RCT/CCT |
| Geiger 2005 | Not RCT/CCT |
| Golembiewski 2005 | Not RCT/CCT |
| Hosseini, 2015 | Prevention of PONV, not treatment |
| Keifer 2007 | Not RCT/CCT |
| Kim 2006 | Not PONV |
| Kim 2007 | Not PONV |
| King 2009 | Not RCT/CCT |
| Koretz 2004 | Not RCT/CCT |
| Lee, 2016 | Prevention of PONV, not treatment |
| Mamaril 2006 | Not RCT/CCT |
| Mcilvoy, 2015 | Not RCT/CCT |
| Morin 2004 | Not RCT/CCT |
| Nale 2007 | Prevention of PONV, not treatment |
| Nanthakomon 2006 | Prevention of PONV, not treatment |
| Phillips 1993 | Prevention of PONV, not treatment |
| Pompeo 2007 | Not RCT/CCT |
| Pongrojpaw 2003 | Prevention of PONV, not treatment |
| Rosén 2006 | Not RCT/CCT |
| Spencer 2004 | Not RCT/CCT |
| Tavlan 2006 | Prevention of PONV, not treatment |
| Tramer 2001 | Not RCT/CCT |
| Visaylaputra 1998 | Prevention of PONV, not treatment |
| Zeraati, 2016 | Prevention of PONV, not treatment |
CCT: controlled clinical trial; PONV: postoperative nausea and vomiting; RCT: randomized controlled trial