“…Serious side effects include cardiac tamponade [43,44], pneumothorax [45,46], endocarditis [47][48][49], hepatitis [50][51][52], chylothorax [53], and spinal cord injury [50,54], and minor side effects include fainting [55,56] and skin reactions [57][58][59][60]. Pneumothorax is the most common mechanical organ injury associated with acupuncture treatment [50,[61][62][63][64], and the related reports are from the United States [65][66][67], Canada [68], The Netherlands [69,70], France [71], Norway [63], Portugal [72,73], Denmark [74], Taiwan [75], Japan [50,76], China [45,77], and Hong Kong [78]. Based on the facts mentioned above, we understand that the safe needling depth for acupuncture therapy is a very important issue for clinical practice.…”