Accidental ingestion of magnets is a growing problem among children, and parents should be aware of this risk, experts say.

In a new study, researchers at a U.K. hospital report two cases of children who required surgery after ingesting multiple magnets.

One case, an 18-month-old child experienced five days of abdominal pain before the hospital discovered she had swallowed 10 small magnetic spheres. In the second case, an 8-year-old child who showed symptoms of appendicitis was found to have swallowed two magnetic strips, each about an inch long.

Small objects that young children swallow can usually pass through their digestive systems without causing any illness or internal damage. However, when several magnetic elements are ingested, the magnets can become attracted to each other within the child's body, and trap soft tissues between them.

In the intestines, this may lead to the development of a fistula, or an abnormal connection between segments of bowel. Both children in the study developed fistulas, but eventually made full recoveries.

Because a child who swallows a magnet often does not initially experience any pain or discomfort, the diagnosis can be delayed, the researchers said.

"We are particularly concerned about the widespread availability of cheap magnetic toys, where the magnetic parts could become easily detached," said study researcher Dr. Anil Thomas George, of the Queen’s Medical Center in Nottingham. "Parents should be warned of the risk of magnet ingestion, particularly in small children."

High-powered ball magnets — which are not in kids' toys, but can be found in adult "stress-relief" desk toys, in which the magnets are used to create patterns or shapes — can also pose risk to children if they come lose. These magnets can lead to holes in the stomach and intestines, intestinal blockage and blood poisoning if swallowed, according to the U.S. Consumer Product Safety Commission (CPSC).

The CPSC recommends keeping small magnets away from young children, looking out for loose magnet pieces and regularly inspecting toys and children's play areas for missing or dislodged magnets.

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