How common does fainting occur during an acupuncture treatment?

Uncommon : This is uncommon however you are likely describing vasovagal syncope which can occur when people see needles and feel overwhelmed with a sudden paradoxical decrease in BP & hr.

Not common.: It can occur with acupuncture but is not common. As a result i ask people to tell me before hand if they have a fear of needles. I lie them down to administer acupuncture. Out of hundreds of treatments - one of my patients fainted. He had not eaten and had fainted previously when he was having blood drawn.