A 33-year-old woman visited an acupuncturist to treat an arm and wrist injury – and left with two collapsed lungs. An investigation into the incident led by New Zealand Health and Disability Commissioner Anthony Hill found that the accident was the fault of the acupuncturist, who had stuck the needles in too deeply.

To treat an injury causing shoulder pain and shortness of breath, the acupuncturist (known only from the case report as Ms B) inserted two needles in an acupressure point called Jian Jing or Gallbladder 21 (GB21) – a risky area that contributes roughly 30 percent of lung collapse cases relating to acupuncture, according to one review. The woman reported pain during the insertion but the needles were left in place for 30 minutes. Then, rotated and removed.

During their removal, the woman reports feeling a sudden onset of pain in her right chest as well as shortness of breath. Ms B's notes show that she had begun to feel a stuffy chest following the second adjustment and slight pain. In response, Ms B said she immediately removed the needles and provided additional treatment, following which the patient was advised to go home and rest despite the fact that she reports still having felt "very uncomfortable".

That evening, the woman's husband took her to the hospital, where staff in the emergency department diagnosed her with bilateral apical pneumothoraces – ie collapsed lung on both sides of the body.

Hill's investigation ruled the acupuncturist had failed to explain the risks of the procedure to the patient sufficiently and did not take appropriate care during the treatment, and was therefore in breach of the health code.

Although uncommon, pneumothoraces or collapsed lung is a very real risk of acupuncture – indeed, it was only this summer, IFLScience reported on a similar incident involving a 79-year-old woman in Portugal. One study found that 0.024 percent of patients experienced a serious adverse health effect (death, organ trauma, or hospital admission) following treatment, while another found 2.2 percent required specific care due to a problem with the procedure.

As well as collapsing lungs, serious adverse effects can include cardiac tamponade, spinal cord injury, and viral hepatitis. One woman reported feeling pain 30 years after an acupuncture treatment caused by needles that had embedded into her spine.

As for the health benefits of acupuncture, the science is less certain. Studies suggest it may well help with conditions such as chronic pain and migraines, but many medical professionals attribute this success more likely to the work of the placebo effect (which appears to work even when you are aware it's a placebo).