Efficacy and Safety of Traditional Chinese Medicine Retention Enema for Endometriosis: A Systematic Review and Meta-Analysis

Background/Objectives: Herbal retention enema is widely used in Traditional Chinese Medicine for the management of endometriosis; however, its clinical efficacy and safety have not been systematically evaluated. Methods: Ten electronic databases were searched up to May 2025 to identify randomized controlled trials evaluating herbal retention enema as a standalone treatment for endometriosis. Primary outcomes included total effective rate and pain-related measures. Risk of bias was assessed using the Cochrane RoB 2 tool. Results: Nine randomized controlled trials involving 614 participants were included. Compared with Western medical therapies, herbal retention enema was associated with greater overall clinical effectiveness (OR = 2.87) and significant improvement in dysmenorrhea. When compared with oral herbal medicine, herbal retention enema demonstrated a higher total effective rate (OR = 7.13). A trend toward improved pregnancy outcomes was observed (p = 0.05). No serious adverse events related to herbal retention enema were reported, and systemic adverse effects were less frequent than with hormonal therapies. Conclusions: Herbal retention enema may represent a potential complementary option for symptom management in endometriosis; however, the certainty of evidence remains low due to important methodological limitations in the included trials. However, given methodological limitations and heterogeneity among studies, further high-quality randomized controlled trials with standardized outcomes and long-term follow-up are required.