Complementary Therapies in Medicine 56 (2021) 1025962Prophet Mohammad (Gole Mohammadi), because they believe that it is a holy plant and its nice aroma reminds them of prophet Mohammad 6. Damask rose contains several components such as glycosides, ter-penes, flavonoids, and anthocyanins; all have a favourable effect on human health 4,5. Different products of this plant have bronchodilator, hypnotic, anti-convulsant, laxative, anti-diabetic, anti-microbial, anti-viral, anti-depressant, anti-inflammatory, anti-cancer, neuro-protective, cardioprotective, hepatoprotective, and antioxidant proper-ties 4,5,7. In addition, analgesic activities of Damask rose are well documented in both traditional and modern medicine, especially in Iran 4,5,7,8. Among herbal medicinal oils used in the Iranian traditional medicine, Damask rose oil has been applied as an analgesic agent for a long time 9. Avicenna, the 10th century Iranian physician, mentioned analgesic properties of Damask rose in the Canon of Medicine more than one thousand years ago 10. Recent clinical trials indicated a great interest in the analgesic effects of Damask rose in different forms of administration, especially aroma-therapy 11–30. Based on available data, studies have focused on pain-reducing effect of aromatherapy with Damask rose in forms of inhalation, vapor diffusion, and massage; however, data are controver-sial. Pain severity induced by musculoskeletal disorders 24, labour 25, and surgery 26 did not differ significantly after administration of inha-lation aromatherapy with Damask rose or the placebo. However, other trials reported analgesic effects of inhalation aromatherapy on pain severity induced by burn dressing change 15,31, labour 16–19,28, surgery 11,12,14,27,29,32, and menstruation 23. In addition, some studies showed that Damask rose aromatherapy with vapor diffusion was more effective against pain induced by labour 22, renal colic 13, and menstruation 21. Moreover, aromatherapy massage and foot bath with Damask rose induced alleviating effects on labour pain and dysmenorrhea 30,33. In addition to recent trials, some narrative and systematic reviews investigated the pain-alleviating effects of Damask rose 4,5,7,8,34. Based on the results of a systematic review on herbal medications for post-surgical pain, a non-significant reduction was observed with regard to the need for rescue medication in patients treated with oral intake of Damask rose blended with ginger compared to those who used the placebo 34. However, in a systematic review of in vitro, animal, and human studies on the efficacy and safety of Damask rose, promising evidence of the pain-alleviating effects of Damask rose in oral, inhala-tion, and massage form was found 7. Moreover, in another systematic review of randomized controlled trials (RCTs) over therapeutic efficacy of Damask rose oil, it was mentioned that aroma-massage therapy or aromatherapy with Damask rose could be effective on different painful conditions 8. These systematic or narrative reviews combined either different administration routes of Damask rose (i.e., aromatherapy, topical treatment, and oral intake) or findings of animal and human studies in their synthesis. In addition, aforesaid reviews missed several relevant studies in their analyses. To the best of our knowledge, neither systematic review nor meta-analysis has ever evaluated the analgesic potencies of aromatherapy with Damask rose. Therefore, this systematic review was carried out to summarize the results of recent RCTs over the effect of aromatherapy with Damask rose in the form of inhalation, vapour diffusion, and massage on reducing the severity of acute pain in adults. Also, we aimed to evaluate the potential effects of treatment by data pooling in a meta-analysis. 2. Material and methods 2.1. Review protocol The study protocol was approved by the Institutional Review Board of Dezful University of Medical Sciences, Dezful, Iran (Approval No: 98046). Also, it was registered in the international prospective register of systematic reviews (Approval No: CRD42020147657). The review was reported based on the recommendations provided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 35 (Supplementary Table 1). 2.2. Data sources The electronic databases, including MEDLINE/PubMed, Scopus, ISI web of science, Cochrane Central Register of Controlled Trials (CEN-TRAL), Embase, ProQuest, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched. Also, a search was done in two Iranian databases of scientific information database (SID, http://www.sid.ir/) and MagIran (http://www.magiran.com), because the use of Damask rose is common in Iranian experimental studies. Moreover, researchers searched the clinical trial registry systems (i.e., Iranian Registry of Clinical Trials, ClinicalTrials.gov, and WHO Inter-national Clinical Trials Registry Platform) to retrieve the finished and ongoing trials. To find more relevant studies, the reference lists of all eligible studies and previous reviews were reviewed manually. 2.3. Search strategy The search strategy for each database is available in Supplementary Table 2. First, all data sources were searched systematically in April 2020. Then, an email alert service was created to identify new studies that might be published after the first search. Finally, a search was conducted on August 10, 2020 to retrieve relevant new eligible studies. In our search strategy, study designs, participants, publication time, and language were deliberately not limited in order to facilitate finding all the relevant studies. All searches were conducted by two researchers (MN and MBBS) independently. The Kappa coefficients (К) for agree-ment between the researchers during the systematic searches showed a range of 0.79 to 0.83, which means a substantial agreement 36. Any uncertainty or disagreement between the investigators during the sys-tematic search was resolved through discussion. 2.4. Inclusion criteria The studies were included if they: (1) recruited adults who experi-enced moderate to severe acute pain (according to the baseline score); (2) were conducted using RCT designs; (3) investigated the effect of aromatherapy using any products of Damask rose in the forms of inha-lation, vapour diffusion, and massage compared to the placebo, no treatment or conventional analgesics; and (4) measured pain severity or analgesic use. We considered pain severity measured by a visual analogue scale (VAS) or other validated scales as the primary outcome and the analgesic use as the secondary outcome. We did not restrict the type of painful conditions experienced by the participants; instead, we used subgroup analysis to investigate any possible differences regarding the effect of treatment on different participants. 2.5. Exclusion criteria Reviews, case reports, commentary, letter to the editor, book sec-tions, theses, conference proceeding, and publications without available English abstracts were excluded. In the case of redundant publications, the study with limited data was excluded. Moreover, the studies were excluded in the case that they: (1) focused on chronic painful conditions (i.e., arthritis, nerve pain, back pain, and fibromyalgia pain); (2) recruited children or older adults; (3) applied Damask rose using oral or topical methods; (4) administered Damask rose blended with other ar-omatic or herbal agents; (5) applied Damask rose using two concurrent methods of administration; (6) used other species of Rosa or other herbal products; and (7) were conducted in animal models or by quasi- experimental design. 2.6. Study selection All investigated records were transferred to Endnote software. In the M. Nasiri et al.