Acupuncture and transcutaneous electrical nerve stimulation (TENS) are non-pharmacological methods that have been used for millennia to relieve pain. As with all complementary treatments, efficacy evaluations face two hurdles: the non-feasibility of double-blinding and the difficulty in identifying the optimal control population or treatment. Nevertheless, recent studies of good methodological quality have demonstrated benefits in many types of pain compared to conventional treatment. The mechanisms of action of acupuncture and TENS, which are increasingly well understood, involve endogenous pain control systems, cerebral plasticity, and nonspecific effects (e.g., expectations and placebo effect). No serious adverse effects have been reported. These data support the more widespread use of non-pharmacological pain management, most notably in patients with chronic pain inadequately relieved by medications alone.