Why do surgeons say no nail polish?

Why Surgeons Say No Nail Polish Before Surgery

It’s a small detail, but one surgeons and anesthesiologists take seriously: you’re often asked to remove nail polish before going under the knife. Why? It all comes down to safety—and a tiny sensor that plays a big role during surgery.

During an operation, medical teams constantly monitor your vital signs, including blood oxygen levels. One of the most common tools used is the pulse oximeter—a small clip-like device usually placed on your fingertip. It works by shining a red light through the skin and measuring how much oxygen your red blood cells are carrying.

Here’s where nail polish becomes a problem. Most nail polishes, especially darker shades like deep reds or purples, can interfere with the sensor’s ability to read that red light accurately. The polish may absorb or scatter the light, leading to false or delayed readings. And in a high-stakes environment like the operating room, even a small delay can matter.

But it’s not just about the machine. Doctors also rely on visual cues. The nail bed is one of the best places to spot cyanosis—when skin turns bluish due to low oxygen levels. Nail polish can mask this crucial sign, making it harder for medical staff to react quickly if something goes wrong.

So while skipping the manicure might seem like a minor inconvenience, it’s really about keeping you safe. As one nurse put it: “We’d rather see your natural nails than your favorite shade of black.”

Bottom line: when it comes to surgery, even the smallest details—like a coat of polish—can make a big difference.