Pain is the most common reason why patients seek medical consultants. Currently available medications, such as nonsteroidal anti-inflammatory drugs, amine reuptake inhibitors, antiepileptic drugs, and opioids, have varying but typically low levels of analgesic efficacy, and are generally coupled with severe side effects. In particular, opioid drugs, the most effective analgesic frequently used in clinical, can cause tolerance, dependence, constipation, and respiratory depression, especially when overdosed. To cope successfully with the opioid crisis, it is of great importance to discover other novel therapies whose mechanisms do not involve the opioid receptors and have superior efficacy and diminished adverse effects.

Recent decades have witnessed substantial progress in understanding the mechanisms of pain in normal states, where it helps protect from damage, as well as in pathological conditions where pain can evolve from symptoms of tissue injury to diseases themselves. Despite these scientific advances, however, the mechanisms of pain, particularly visceral and chronic pain conditions, remain obscure and subsequently the management of pain remains a challenge. Arguably, clinicians are not much more advanced now in their capacity to either diagnose or effectively treat patients suffering from pain. Therefore, the search for an alternative and well-tolerated therapy to achieve better pain relief with fewer adverse effects is of great importance. Acupuncture and related procedures, such as electroacupuncture and dry needling, have been increasingly used as an integrative or complementary therapy in the management of varied pain conditions. It has been indicated that multiple factors contribute to the variability of acupuncture's effects, including needling techniques, number of stimulations, duration of needle retention, acupuncture point specificity, number of sessions of treatment, individual variation, and other subjective (psychological and emotional) elements. In recent decades, a large amount of evidence from basic studies and clinic observations has been accumulated to account for the beneficial efficacy and underlying mechanisms, however, much still remains controversial on whether acupuncture works rather than any effect being solely the placebo effect, and the mechanisms behind these effects from the perspective of cells and molecular biological processes.

This Special Issue aims to address these issues by collecting high quality relevant submissions. Prospective authors are invited to contribute their preclinical, clinical, and review articles, and experimental studies concerning the molecular mechanisms behind the therapeutic efficacy of acupuncture are especially welcome. In addition, contributions exploring the nature of the meridians and the microstructures of individual acupoints are also encouraged. To settle the long-lasting argument in the biomedical community, it is of great necessity to carry out such studies by means of classical measures integrated with genetic, developmental, and other state-of-the-art methods. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Basic studies to probe the mechanisms underlying pain relief by acupuncture
• Experimental research exploring the nature of meridians
• Laboratory work to anatomically delineate the microstructures and microenvironments of acupoints
• Clinical trials highlighting pain management by acupuncture
• Pain management by other options, such as moxibustion or dry needling
• Standardisation of acupuncture, emphasising pain treatment
• Narrative and systematic reviews to summarise the treatment of pain by acupuncture
• Application of acupuncture in rehabilitation, particularly for pain relief and function improvement
• Development of apparatuses with respect to acupuncture and other non-invasive procedures
• Education and communication of acupuncture