The New England Journal of Medicine reports that the girl from Illinois complained of a five-month history of pain and swelling in her abdomen, vomiting after eating and a 40-pound weight loss. Till that bout she had been quite healthy.

The gastrointestinal specialists put her through a scan and a large mass was detected. Still it was not clear what it was all about. Then they lowered a scope through her esophagus.

It revealed "a large bezoar occluding nearly the entire stomach," wrote Drs. Ronald M. Levy and Srinadh Komanduri, gastroenterologists at Rush University Medical Center in Chicago, Illinois. A bezoar is a hairball.

"On questioning, the patient stated that she had had a habit of eating her hair for many years -- a condition called trichophagia," they wrote.

"It seemed like she'd been doing this for several years," Levy told CNN.

The woman underwent surgery to remove the mass of black, curly hair, which weighed 10 pounds and measured 15 inches by 7 inches by 7 inches, the doctors said.

Five days later, she was eating normally and was sent home.

A year later, the pain and vomiting were gone, the patient had regained 20 pounds "and reports that she has stopped eating her hair."