Hello, this is attorney Oh Seung-hyun of Cheongchul Law Firm.

In April 2026, a woman in her thirties who had undergone a uterine procedure discovered a palm-sized piece of gauze inside her body a week later during menstruation. The doctor first said it was "a dissolvable hemostatic agent," and later admitted it "appears not to have been removed." Yet after four months of investigation the police decided not to refer the case for prosecution (a finding of no charge). The patient is bewildered. The doctor admits closing the incision with the gauze left inside — so why is there no charge? And what should she do now?

Incidents in which a foreign body remains in the patient after surgery — retained surgical foreign bodies — are preventable medical accidents reported worldwide. Below we explain how courts assess this type of accident and why criminal and civil outcomes can differ.

What gets left inside

Foreign bodies retained during surgery fall into three broad categories. The most common is surgical gauze: when several pieces are used to absorb bleeding or achieve hemostasis, the count may be wrong, or a piece soaked in blood may adhere to tissue and be missed. The second is drains and tubes, which are inserted to drain exudate from the surgical site and must later be removed, but are sometimes overlooked before closure. The third is fragments of surgical instruments — scalpel tips, needles, clips and other metal pieces that break off or become detached during surgery and remain in the body.

Major hospitals today use surgical gauze embedded with X-ray detectable material together with automated counting systems, which has greatly reduced the incidence of retained foreign bodies. They still occur, however, at smaller clinics, in urgent emergency operations, and where surgery runs long.

The medical team's duty of care — "thoroughly confirm and remove"

Courts hold consistently: "On completing surgery, a doctor has a duty of care to thoroughly confirm that no gauze, instruments or other items used during the procedure remain in the body, and to remove them." This duty applies regardless of the difficulty of the surgery or whether it was an emergency. Where a foreign body is found in the body, fault is presumed unless the medical team can itself prove that it discharged this duty of confirmation.

This is an important feature distinguishing these cases from ordinary medical negligence litigation. In ordinary medical negligence cases the patient must prove the medical team's fault. In retained foreign body cases, however, the very fact that a foreign body was found effectively presumes fault (applying the doctrine of res ipsa loquitur), and the medical team must rebut it by showing that appropriate confirmation measures were taken. In effect, the burden of proof shifts.

Cases in which courts found fault

(1) Gauze and a metal rod retained after nasal sinus surgery — damages in the tens of millions of won

A patient who had undergone surgery for a nasal sinus condition visited another hospital years later after persistent discharge of foul-smelling yellow fluid from the nasal cavity; gauze and what appeared to be a metal rod used during the original surgery were found and removed by further surgery. The court found both fault — breach of the duty to thoroughly confirm and remove surgical items — and causation, in that the long-retained foreign bodies caused the worsening of chronic nasal sinus disease, and ordered payment of the full cost of the corrective surgery plus consolation money in the tens of millions of won.

(2) Drain (tube) not removed before closure — left for two years, consolation money of KRW 7 million

After surgery to remove a benign tumor, a silastic drain for fluid discharge was left in place when the wound was closed and remained in the patient's body for about two years. The Ulsan District Court clearly found the doctor at fault. In that case, however, the drain had not damaged nerves or blood vessels, was removed without difficulty by a simple procedure, and the patient had been able to lead a normal daily life; reflecting these factors, consolation money was assessed at KRW 7 million (Ulsan District Court decision). As this shows, the degree of actual harm caused by the retained object heavily influences the amount awarded.

Even where there is no criminal charge, civil compensation is a separate matter

Why is there no criminal charge — the standard of proof for causation differs

In the 2026 obstetrics and gynecology gauze case, the police decided not to refer the case on the ground that "although fault in failing to remove the gauze is acknowledged, causation between the pain, high fever and chills the patient complained of and the gauze in her body was not sufficiently proven." Criminal punishment requires proof to the level of excluding reasonable doubt — that is, causation between the pain and the foreign body must be proven "beyond doubt." In a 1999 Supreme Court decision (99Do3711) as well, a scalpel fragment remained in the body during spinal surgery, yet a criminal acquittal was rendered on the ground that the fragment had not damaged nerves or blood vessels.

Civil cases are different — the presumption of causation applies

In civil damages litigation the standard differs. The Supreme Court has held that "where the patient proves an act involving medical fault and proves that no cause other than the medical treatment could have intervened between that act and the result, causation between the medical treatment and the result may be presumed," thereby easing the patient's burden of proof (Supreme Court Decision 98Da50586 of January 21, 2000, among others). The very fact that a foreign body remained in the body is evidence of fault, and the pain, infection and need for further surgery experienced during that period support a presumption of causation. A decision not to refer a criminal case therefore does not prevent a civil action.

What to do immediately after a foreign body is discovered

(1) Preserve the foreign body itself

If you discover or discharge a foreign body, preserve the object itself where possible and photograph it. In the 2026 case, the size of the gauze actually discharged (palm-sized) became important evidence. Where the object is removed by further surgery, ask that hospital to preserve and photograph the removed item.

(2) Immediately obtain copies of the operative and medical records

You should obtain the operative record from the hospital that performed the original surgery (including pre- and post-operative gauze count records), the nursing records and the anesthesia records. Checking whether gauze counts are recorded and whether the counts match before and after surgery makes it possible to assess whether the medical team discharged its duty of confirmation. Requesting these records immediately after learning of the incident reduces the risk of later alteration.

(3) Obtain the opinion letter and treatment receipts from the hospital performing the corrective surgery

Obtain from the hospital that removed the foreign body a medical certificate or opinion letter stating that "further surgery was performed to remove a foreign body." The cost of the corrective surgery and subsequent treatment can be claimed as actual damages. Pain, inconvenience and mental suffering during the period the foreign body remained provide grounds for consolation money.

Practical checkpoints

• If you have unexplained pain, signs of infection (fever, chills, discharge) or a persistent sensation of a foreign body after surgery, first confirm whether a foreign body remains by having X-ray or CT imaging at a hospital other than the one that operated. The operating hospital may pass over a foreign body even when it is found.

• If the doctor explains that "this material dissolves" or "it will be absorbed," inspect the removed material yourself and photograph it. If it later turns out to be gauze, the doctor's initial explanation itself becomes important evidence.

• Even if you file a criminal complaint and receive a decision not to refer the case, a civil damages action is separate. Criminal and civil proceedings apply different standards of proof, and in retained foreign body cases the presumption of fault applies in civil proceedings, which is more favorable to the patient.

• The longer the foreign body remains, the greater the resulting infection and need for further surgery, and the larger the object, the higher courts tend to assess damages. Conversely, if the object is very small and has not affected nerves or blood vessels, the result may be criminal acquittal and only a small amount of consolation money in the civil case.

• In retained foreign body cases it is important to work with a medical litigation attorney from the very first stage of establishing the facts, because patients often end up signing settlements with hospitals for less than their actual loss.

Being told the surgery went well, only to have a foreign body emerge from your body, is an indescribable shock. What feels even more unjust is when the doctor admits the mistake yet the conclusion is that "there is no crime." But criminal and civil liability are different. Once fault is established, compensation for the pain, corrective surgery, infection treatment costs and mental suffering caused by the foreign body can properly be claimed through a civil action.