Effectiveness and safety of acupuncture for functional constipation: An updated overview of systematic reviews

A B S T R A C T Objective To synthesize updated evidence on the effectiveness and safety of acupuncture for functional constipation (FC), critically appraise the quality and credibility of the available evidence, and assess the overlap of primary studies across systematic reviews (SRs). Methods We searched six databases from inception through June 10, 2026, for SRs and meta-analyses of acupuncture for FC. Two reviewers independently screened studies, extracted data, and assessed methodological quality, risk of bias, reporting quality, and evidence certainty using A MeaSurement Tool to Assess Systematic Reviews 2 (AMSTAR2), Risk of Bias in Systematic Reviews (ROBIS), Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 (PRISMA 2020), and Grading of Recommendations Assessment, Development and Evaluation (GRADE), respectively. We synthesized findings narratively and assessed overlap among primary studies using citation matrices, covered area, and corrected covered area (CCA). Results Fifteen SRs published between 2013 and 2025 were included. Compared with sham acupuncture, acupuncture consistently improved weekly complete spontaneous bowel movements (CSBMs), Bristol Stool Form Scale (BSFS), total effective rate, Cleveland Clinic Constipation Score (CCCS), and quality of life. Compared with Western medicine, acupuncture consistently improved quality of life, whereas results for weekly CSBMs, spontaneous bowel movements (SBMs), CCCS, and total effective rate were heterogeneous. For the primary studies assessing efficacy outcomes, the CCA was 2.82%, indicating a slight overlap. Adverse events were generally mild; no serious acupuncture-related events were reported. However, only 29.6% (16/54) of the outcome-specific certainty assessments were rated as high or moderate, and all SRs exhibited critically low methodological quality and a high risk of bias. Conclusions Acupuncture may improve several clinically relevant FC outcomes, particularly compared with sham acupuncture; evidence against Western medicine is less consistent. Because the included SRs generally had poor methodological quality and drew predominantly on low-certainty evidence, high-quality randomized controlled trials and methodologically rigorous SRs are warranted.