The medical perspective of cupping therapy: Effects and mechanisms of action.

Cupping Therapy (CT) is an ancient method and currently used in the treatment of a broad range of medical conditions. Nonetheless the mechanism of action of (CT) is not fully understood. This review aimed to identify possible mechanisms of action of (CT) from modern medicine perspective and offer possible explanations of its effects. English literature in PubMed, Cochrane Library and Google Scholar was searched using key words. Only 223 articles identified, 149 records screened, and 74 articles excluded for irrelevancy. Only 75 full-text articles were assessed for eligibility, included studies in this review were 64. Six theories have been suggested to explain the effects produced by cupping therapy. Pain reduction and changes in biomechanical properties of the skin could be explained by "Pain-Gate Theory", "Diffuse Noxious Inhibitory Controls" and "Reflex zone theory". Muscle relaxation, changes in local tissue structures and increase in blood circulation might be explained by "Nitric Oxide theory". Immunological effects and hormonal adjustments might be attributed to "Activation of immune system theory". Releasing of toxins and removal of wastes and heavy metals might be explained by "Blood Detoxification Theory". These theories may overlap or work interchangeably to produce various therapeutic effects in specific ailments and diseases. Apparently, no single theory exists to explain the whole effects of cupping. Further researches are needed to support or refute the aforesaid theories, and also develop innovative conceptualizations of (CT) in future.