It has been known for thousands of years that acupuncture can relieve pain.However

the efficacy of acupuncture analgesia(AA)now has to be reconsidered due to negative reports from western countries.In the present study

the possible correlation between caffeine and the difference in AA in China and western countries was determined using the following factors:1)caffeine and pain;2)adenosine

adenosine receptor and caffeine;3)AA and caffeine.As a non-selective antagonist of the adenosine receptor

caffeine at low doses can be used as an adjuvant analgesic

and can augment antinociception combined with other analgesics.Caffeine can act as an important neural modulator

and adenosine can produce antinociception when combined with the A1 receptor located in spinal

supraspinal and peripheral tissue.A preclinical study demonstrated that caffeine at moderate doses could inhibit AA efficacy following plantar incision surgery in a mouse model.Caffeine is present in various foods

especially coffee

and approximately 85% of adults in western countries consume coffee regularly.Therefore

by reconsidering the correlation between caffeine

adenosine receptor and AA

and by determining the possible relationship between caffeine intake habits and AA efficacy

these findings will demonstrate the differences in AA between Chinese and western populations.