Mainstream medicine commonly categorizes acupuncture as “alternative and complementary,” a designation that reflects conceptual gaps in existing treatment classification systems. Integrating complementary medicine into the mainstream medical system requires a conceptual adjustment. Here, I propose a mechanism-based 5R classification—Removing, Repairing, Replacing, Replenishing, Regulating—to systematically categorize therapies. Based on this classification, acupuncture and its related interventions fall under functional regulation therapy. This framework offers a unified, functional perspective that facilitates the integration of complementary medicine into mainstream medical taxonomy.