Acupuncture is a low-risk procedure when performed by a trained practitioner, but it is not risk-free. A large prospective survey of over 34,000 treatments found minor adverse events in roughly 1 in 800 sessions, with no serious complications recorded at all.1Europe PMC / BMJ. The York acupuncture safety study: prospective survey of 34 000 treatments by traditional acupuncturists That said, the medical literature does contain case reports of punctured lungs, cardiac injuries, infections, and broken needles, so “safe” does not mean “harmless under all circumstances.” The gap between typical experience and worst-case outcomes is worth understanding.
What Happens Most of the Time
The side effects people actually experience during or after acupuncture are overwhelmingly minor. A mapping of 535 systematic reviews found that pain at the needle site was the most frequently reported issue, followed by bleeding or bruising, and then hematoma (a small pocket of blood under the skin).2PubMed Central. Adverse effects associated with acupuncture therapies: An evidence mapping from 535 systematic reviews Other common complaints include headache, itchiness at the needle site, redness, numbness, and brief worsening of the symptom being treated. A separate review adds vasovagal reactions to that list, meaning things like feeling tired, dizzy, or lightheaded during or right after a session.3PubMed. Acupuncture: A Review of the Safety and Adverse Events and the Strategy of Potential Risk Prevention
These reactions tend to be short-lived. A small bruise might last a few days; post-session fatigue usually clears within hours. The York safety study, which tracked outcomes across 573 practitioners, recorded bleeding in 15 out of 34,000 treatments and bruising in 14, with no event requiring medical attention.1Europe PMC / BMJ. The York acupuncture safety study: prospective survey of 34 000 treatments by traditional acupuncturists For most people, the worst part of a session is a momentary sting when a needle goes in.
Serious Organ Injuries
The most alarming acupuncture complications involve a needle reaching organs it was never meant to touch. Pneumothorax, a collapsed or partially collapsed lung, is the best-documented serious injury. It happens when a needle inserted into certain points on the upper back or chest wall punctures the thin membrane surrounding the lung. A review of traumatic complications found that injuries have been described in the lungs, abdominal organs, the nervous system, and blood vessels, with deaths recorded from both pneumothorax and cardiac tamponade.4PubMed. Traumatic complications of acupuncture
These cases are individually dramatic. One report describes a 28-year-old woman who developed intense right-sided chest pain and breathlessness after needles were placed in her chest wall. She was diagnosed with a tension pneumothorax, a life-threatening form of lung collapse where air pressure builds and shifts the central chest structures to the opposite side, requiring emergency chest tube insertion.5PubMed Central. Navigating the Needles: Unveiling the Risks of Acupuncture: A Case Report Her symptoms had a delayed onset, which the authors attributed to the small size of the hole the needle created. In another case, a 62-year-old man developed cardiac tamponade, where blood fills the sac around the heart and compresses it, after acupuncture to the area below the sternum. Surgeons found a shredded branch of his right coronary artery and had to ligate the damaged vessel to stop the bleeding.6PubMed Central. Cardiac tamponade complicated by acupuncture: hemopericardium due to shredded coronary artery injury
The common thread in these cases is anatomy. Several traditional acupuncture points sit directly above thin-walled body cavities. A needle inserted too deeply or at the wrong angle can reach the pleural space, the pericardium, or the peritoneum. Practitioners trained in anatomy know how deep they can safely go at each point, which is why these injuries are strongly linked to practitioner skill and not to the procedure itself.
Infections, Then and Now
Infection was once the single largest category of serious acupuncture complications, driven largely by hepatitis transmission through reusable needles. That picture has changed substantially. A systematic review of case reports found that the main infection source had shifted from hepatitis caused by reusable needles to bacterial infections caused by skin contact at needle sites, with no hepatitis cases identified in the more recent literature.7PubMed Central. Adverse Events of Acupuncture: A Systematic Review of Case Reports The adoption of single-use, pre-sterilized needles in most regulated settings essentially eliminated the bloodborne pathogen risk.
Bacterial infections still occur, though, and they can be serious. The organisms involved are usually skin bacteria like staphylococcus that get pushed beneath the surface when a needle enters. This is more likely when skin preparation is skipped, when the practitioner’s hands are not properly cleaned, or when needles are left in for extended periods. If you notice increasing redness, warmth, swelling, or pus at a needle site in the days after treatment, see a doctor rather than waiting it out.
Broken and Retained Needles
Acupuncture needles are thin, typically between 0.16 mm and 0.30 mm in diameter, and can break if a patient moves suddenly or if the needle is defective. When a fragment stays inside the body, it often causes no symptoms at all. A radiology case report notes that in most cases these fragments can remain in place permanently without problems, though they occasionally migrate in patients without much body fat, and have been found in organs as distant as the liver, pancreas, and kidney.8PubMed Central. Permanent Permanently Retained Acupuncture Needles: Radiographic Findings and Case Report Retained fragments can also trigger foreign body granulomas or contact dermatitis.
When retained needles do cause trouble, surgery is usually required. One patient developed severe back pain years after acupuncture and was found to have two deteriorated broken needle pieces lodged near her T12 vertebra; they were extracted by laparoscopy and she recovered fully within five days.9PubMed Central. Surgical Treatment for a Broken Acupuncture Needle in the Retroperitoneal Space: A Case Report In an even more striking case, a needle fragment was found in a patient’s right lung, presumably having migrated from a lower-body insertion site years earlier. It was removed through a wedge resection of the lung lobe, and the patient recovered well.10PubMed Central. Intrapulmonary migration of a fractured acupuncture needle: a case report These cases are exceedingly rare, but they underscore why practitioners should inspect needles before use and count them after removal.
Electroacupuncture Has Its Own Risks
Electroacupuncture passes a small electrical current between pairs of inserted needles. It adds a layer of risk that standard needling does not carry. A systematic review of electroacupuncture adverse events found that potential complications include skin pigmentation, syncope, muscle spasm, electrical burns, internal organ injury, and cardiac emergencies including implantable cardioverter-defibrillator shock.11PubMed. Adverse events related to electroacupuncture: a systematic review of single case studies and case series The cardiac concern is especially relevant for people with pacemakers or defibrillators, because the electrical current can interfere with the device’s programming. Electroacupuncture is generally avoided entirely in patients with permanent pacemakers for this reason.12PubMed Central. Electroacupuncture and permanent pacemaker: a study on safety and electromagnetic interference
If you have any implanted electrical device, mention it before treatment begins. Standard manual acupuncture without electrical stimulation does not carry this risk.
People on Blood Thinners
A common concern is that acupuncture might cause dangerous bleeding in people taking anticoagulants like warfarin or heparin. The evidence here is more reassuring than many practitioners expect. A systematic review of acupuncture safety in anticoagulated patients found that across nearly 4,000 treatments, only one moderate bleeding event occurred (a large hip hematoma in a patient on warfarin), for a rate of about 0.003%.13PubMed Central. Acupuncture Safety in Patients Receiving Anticoagulants: A Systematic Review Minor blood-spot bleeding at needle sites, which also occurs in people not on blood thinners, happened in about 15% of treatments in one case series and was controlled with simple pressure.
A larger case-control study using real-world data showed a more detailed picture. The overall rate of minor bleeding was about 8 per 10,000 needle insertions, and major bleeding was roughly 4 per 100,000 insertions. Anticoagulants did raise the odds of minor bleeding, but the increase in major bleeding risk did not reach statistical significance. Warfarin, direct oral anticoagulants, and heparin each carried elevated minor bleeding risk, while antiplatelet drugs like aspirin did not significantly increase bleeding at all.14PubMed. Bleeding risk after acupuncture in patients taking anticoagulant drugs: A case control study based on real-world data A smaller study found that microbleeding at needle sites in warfarin patients stopped within 20 seconds in over 90% of cases, with no extensive bleeding observed.15PubMed Central. Does acupuncture increase the risk of bleeding in patients taking warfarin?
The takeaway is not that blood thinners are a non-issue, but that with appropriate technique, including shallower needling and careful pressure after withdrawal, acupuncture can be safely administered to most anticoagulated patients. Your practitioner should know what medications you are on before the first needle goes in.
Pregnancy and So-Called Forbidden Points
Traditional Chinese medicine identifies certain acupuncture points as “forbidden” during pregnancy, based on the belief that stimulating them could trigger contractions or miscarriage. Modern research paints a less alarming picture. A review of the scientific literature found no evidence of harm following needling at these traditionally forbidden points, even though acupuncture does appear capable of stimulating uterine contractions or cervical changes in some cases. The reviewers concluded that these effects do not translate into adverse pregnancy outcomes.16PubMed Central. The safety of obstetric acupuncture: forbidden points revisited
That said, a systematic narrative review looking specifically at preterm contractions as an outcome recommended caution. The strength of evidence was found to be insufficient to recommend using forbidden points before 37 weeks of pregnancy, mostly because the existing trials had small, highly selected patient populations and notable risk of bias.17PubMed Central. Using Forbidden Points in Pregnancy: Adverse Outcomes and Quality of Evidence in Randomized Controlled Trials—A Systematic Narrative Review The picture is one of probable safety but not established certainty. If you are pregnant, an experienced practitioner will know which points to avoid in the first two trimesters and when those same points might actually be useful for labor preparation closer to term.
Children
Pediatric acupuncture raises its own set of concerns because children’s bodies are smaller, their anatomy is different (infants’ skull fontanelles may not yet be closed, for instance), and they are less able to hold still. A review of pediatric evidence calculated a rate of about 1.55 adverse events per 100 treatments and described the overall risk as low, comparable to the risk of taking penicillin.18PubMed Central. Safety and efficacy of acupuncture in children: a review of the evidence A more comprehensive systematic review identified 279 adverse events from published literature, of which 253 were mild (pain, bruising, bleeding) and 25 were serious, including infections, one case of cardiac rupture, one pneumothorax, and nerve impairment. The review noted that many of the serious events appeared to have been caused by substandard practice.19PubMed. The safety of pediatric acupuncture: a systematic review
Pediatric acupuncture often uses fewer needles, thinner gauges, and shorter retention times than adult treatment. Some pediatric practitioners use non-insertive tools that press on acupoints without piercing the skin, which eliminates the needle-related risks entirely.
Allergic and Skin Reactions
Most modern acupuncture needles are made of stainless steel, but some contain trace amounts of nickel, chromium, or silicon in the alloy. For people with nickel sensitivity, which is one of the most common contact allergies, this can trigger localized eczematous eruptions at the puncture site.20PubMed Central. Nickel contact dermatitis from hypodermic needles The reaction typically looks like a small patch of red, itchy, blistering skin right where the needle was placed. If you already know you react to nickel jewelry, mention it to your practitioner. Nickel-free needles exist and can be requested.
How Dry Needling Compares
Dry needling, often performed by physical therapists rather than acupuncturists, uses the same type of thin filiform needle but targets myofascial trigger points rather than traditional acupuncture meridians. Its minor adverse event rate is substantially higher. A large survey reported that about 37% of dry needling treatments resulted in at least one minor event, with bleeding occurring in 16%, bruising in about 8%, and pain during the procedure in roughly 6%. The rate of major adverse events was less than 0.1%, or about one per 1,000 treatments.21PubMed Central. Adverse Events Associated with Therapeutic Dry Needling The higher rate of minor side effects likely reflects the technique: dry needling often involves deeper insertion and more aggressive needle manipulation to elicit a “twitch response” in the muscle. The serious risks, like pneumothorax, are largely the same as for acupuncture.
Laser Acupuncture as a Needle-Free Option
For people who want the point-stimulation concept of acupuncture without being pierced, laser acupuncture uses low-level laser light applied to acupoints. A systematic review of 21 randomized controlled trials found that the majority reported laser acupuncture to be safe and free of adverse events. Six trials reported mild effects like tingling, temporary pain flare-ups, or transient fatigue, all of which resolved on their own within 24 hours.22PubMed Central. The Safety of Laser Acupuncture: A Systematic Review By removing the needle entirely, laser acupuncture eliminates the risks of bleeding, infection, organ puncture, and needle breakage. Whether it delivers the same clinical benefit as needle-based acupuncture is a separate question with less settled evidence.
Why Training and Regulation Matter So Much
The recurring theme across serious acupuncture injuries is practitioner error, not an inherent flaw in the procedure. A review of safety strategies concluded that most adverse events are linked to practitioner mistakes, patient-specific factors, or inadequate safety protocols, and that countries with rigorous certification processes report fewer adverse events.23PubMed Central. Advancing Safety in Acupuncture: Strategies, Best Practices, and Training for a Risk-Free Practice A companion review emphasized the need for global safety standards including mandatory accreditation, licensing, the use of sterilized single-use needles, and continuous education programs.24PubMed Central. How to Improve Safety in Acupuncture Clinical Practice?
Regulation varies widely. In many U.S. states, licensed acupuncturists complete a master’s-level program that includes extensive anatomy training. In other countries and in some U.S. contexts, practitioners with minimal needle training may offer acupuncture-like services. An analysis of malpractice claims from 1990 through 1996 found that claims against acupuncturists occurred less frequently and involved less severe injury than claims against physicians during the same period.25JAMA. Medical Malpractice Implications of Alternative Medicine A Korean analysis of acupuncture-related disputes found that 65% of reviewed cases were judged to have a low possibility of medical malpractice, and acupuncture-specific disputes were significantly less likely to be deemed serious malpractice compared to non-acupuncture traditional medicine disputes.26Journal of Acupuncture Research. Analysis of Traditional Medical Disputes: Data from the Korean Acupuncture and Moxibustion Medicine Society (2013-2017)
Comparing Risk to Conventional Pain Treatments
Risk never exists in a vacuum. If you are considering acupuncture for pain, the relevant comparison is not acupuncture versus doing nothing; it is acupuncture versus whatever else you might use instead. A white paper from an academic pain consortium found that acupuncture had fewer side effects than NSAIDs like ibuprofen and naproxen, while showing small but real advantages over NSAIDs for certain pain outcomes.27Pain Medicine. Acupuncture Therapy as an Evidence-Based Nonpharmacologic Strategy for Comprehensive Acute Pain Care: The Academic Consortium Pain Task Force White Paper Update NSAIDs carry risks of gastrointestinal bleeding, kidney damage, and cardiovascular events with long-term use. Opioids carry addiction and overdose risks that hardly need explaining. Acupuncture’s side-effect profile of occasional bruising and rare serious events looks different in that context than it does in isolation. This does not mean acupuncture is always the better option for any given pain problem, but it reframes what “dangerous” means when the alternatives carry their own well-documented harms.