Background: People with medically unexplained physical symptoms (MUPS) are helped by interventions that combine physical and psychological explanations and treatment. Traditional acupuncture may offer such a perspective, but its use for these patients has not been investigated. Aim: To ascertain how patients with MUPS perceive and experience five-element acupuncture treatment. Design and setting: A longitudinal qualitative interview study, nested in a randomised controlled trial was carried out in four general practices in socioeconomically diverse areas of London. Method: A purposive sample of 20 trial participants was interviewed twice, at the start and the end of 6 months of acupuncture treatment. Semi-structured interviews were transcribed, coded, and analysed thematically, summarising both across-case as themes and within-case individual vignettes. Results: Acupuncture, initially accepted as 'just another referral' - one like many others that had been tried and proved unsuccessful — was valued for the amount of time allotted with a caring practitioner who listened and responded, as well as for the interactive and holistic nature of the sessions. These attributes encouraged many patients to take an active role in their treatment, including making cognitive or behavioural lifestyle changes. Interviewees cited a wide range of changes in their health that spanned physical, psychological, and social dimensions. These were largely positive and included an increase in physical and/or mental energy, as well as feelings of greater personal control, calmness, and relaxation. Three interviewees reported worsening health but did not ascribe this to acupuncture. Conclusion: Many patients who were treated with five-element acupuncture perceived a range of positive effects and appeared to take on a more active role in consultations and self-care.