Before biting into this sandwich, take a closer look. Toothpicks have been known for hurt thousands of other people every year as plane crashes or shark attacks.

The danger that only one toothpick can represent has been highlighted in a recent case study published by the New England Journal of Medicine about a man who almost died while swallowing a toothpick. He was hiding in a sandwich and he did not know he had swallowed it – any more than his doctors. While he continued to be sick, scan after scan, nothing was revealed; these small wooden objects do not appear in medical imaging.

PHOTO: Sandwich triangles welded with toothpicks sit on a cutting board in an undated photo.PHOTO STOCK / Shutterstock

The triangles sandwiches held together with toothpicks are sitting on a cutting board in an undated photo.

These sharp and pointed sticks used to clean teeth have been around for thousands of years. researchers found toothpick gorges in the teeth of a Neanderthal 130,000 years ago. The toothpicks were carved in sticks until the 1880s, when a Massachusetts businessman started their mass production with machines, making millions of toothpicks a day.

Toothpick death is unusual – most injuries are not life-threatening. If someone swallowed a toothpick, he might well choke it off.

This can also go unnoticed in the stomach. The acid in the stomach does not break down wooden or plastic objects as it destroys food. The toothpick can end up in the intestines and pierce a hole in the intestines or artery, causing infection, bleeding, sepsisand even death.

PHOTO: A stethoscope is placed on an X-ray.PHOTO STOCK / Getty Images

A stethoscope is based on an X-ray.

The young man participating in the medical study had recurrent fevers and abdominal pain after bowel bacteria infiltrated his blood through a bite of toothpicks in his gut. A series of antibiotics could slow down the infection, but it still came back. Even when the doctors examined his intestine with a colonoscopy, the hole was so small that we could not see it. It was only after the operation that the doctors discovered that the toothpick was lodged in an intestinal artery.

The man has survived and his case is rare, but far from ever seen. Children are most at risk, so toothpicks should be kept out of reach or not used at all.

Azka Afzal, MD is a resident physician at Baylor College of Medicine in Houston and a member of ABC News Medical Unit.