Objectives: Idiopathic Environmental Intolerance (IEI) is an acquired disorder with multiple recurrent symptoms, which is associated with diverse environmental factors that are tolerated by the majority of people. IEI is an illness of uncertain aetiology, making it difficult to treat using conventional medicine.Therefore, there is a need for novel therapies to control the symptoms of IEI. The objective of this study was to evaluate the feasibility and impact of aromatherapy massage for individuals with IEI.Design: Non-blinded crossover trial Setting: IEI patients who attended a clinic in Sapporo city were recruited, and sixteen patients were enrolled. Participants were clinically examined by an experienced medical doctor and met the criteria included in the working definition of IEI disorder.Interventions: During the active period, participants received four one-hour aromatherapy massage sessions every two weeks. During the control period, the participants did not receive any massages.Main outcome measurements: Scores on the IEI-scales trigger checklist, symptoms, life impact, and the State Anxiety Inventory were assessed before and after each period. Short-term mood enhancement was evaluated using the Profiles of Mood Status (POMS) before and after sessions.Results: Due to period effects, evaluation of the results had to be restricted to the first period, and the result showed no effect of intervention. All six sub-scales of the POMS improved after each session.(mean score differences: 4.89 to 1.33, p<0.05).Conclusions: Aromatherapy was well tolerated by subjects with IEI; however, aromatherapy, as applied in this study, did not suggest any specific effects on IEI condition.