Background <p>Mindfulness-based interventions, such as mindfulness-based stress reduction (MBSR), are efficacious mind–body treatments for chronic pain, though their modest effect sizes suggest room for improvement. Notably, recent studies indicate that mindfulness meditation does not engage the endogenous opioid system, which plays an important role in analgesia. Therefore, exploring the combination of a mindfulness-based intervention with a non-opioid treatment that activates this system is warranted. Open-label placebo (OLP), a placebo that is given to a participant without deception, has shown significant promise as a safe and potentially effective analgesic, with studies indicating its effects are mediated by the release of endogenous opioids. This study aims to evaluate the feasibility and acceptability of combining MBSR and OLP treatment compared to each intervention alone for chronic pain in a three-arm randomized controlled trial (RCT).</p> Methods <p>This study will include an 8-week exposure to one of three treatments for individuals with chronic pain: MBSR-only, OLP-only, or a combined MBSR + OLP intervention. Participants will attend four in-person sessions (baseline assessment, randomization session, mid-treatment assessment, and posttreatment assessment), followed by an online assessment at a 3-month follow-up. MBSR sessions will be conducted live via Zoom. Participants in OLP groups will take placebo pills twice daily, with adherence monitored using an electronic pill bottle cap and urine riboflavin tracer testing. Daily diary assessments will be completed over 7-day periods at baseline, mid-treatment, post-treatment, and 3-month follow-up.</p> Discussion <p>Findings from this single-site feasibility RCT will help refine and optimize study protocols needed for a future, fully powered multi-site efficacy trial.</p> Trial registration <p><a href="https://clinicaltrials.gov/study/NCT06720909?cond=NCT06720909&amp;rank=1">NCT06720909</a>. Registered 12/06/2024.</p>