ObjectiveTo evaluate the efficacy and safety of acupoint application for post-stroke depression (PSD) by regulating gastrointestinal function. A secondary objective is to explore the potential mechanism underlying this approach from the perspective of gut microbiota.MethodsThis multicenter, randomized, double-blind (patients and assessors), placebo-controlled trial will enroll 80 patients with PSD, and include a 1-week run-in period, a 4-week treatment phase, and a 12-week follow-up. Eligible participants will randomly be assigned in a 1:1 ratio to either the acupoint application or placebo (non-acupoint) groups. Treatments will be administered thrice weekly for 4 weeks. The primary outcome is change in the Hamilton Rating Scale for Depression (HAMD) score. Secondary outcomes include the Beck Depression Inventory (BDI), 36-Item Short-Form Health Survey (SF-36), Barthel Index of Activities of Daily Living, Social Adaptation Self–Evaluation Scale (SASS), and gut microbiota profiling. All outcomes will be assessed at baseline (prior to treatment), during treatment (weeks 2 and 4), and during follow-up (weeks 8, 12, and 16). The Treatment Emergent Symptom Scale (TESS) will be used for evaluation throughout the 4-week treatment phase.DiscussionThe results of this study will provide important evidence supporting a novel treatment strategy for PSD that targets gastrointestinal regulation, potentially informing future clinical practice.