A 13-year-old boy was rushed to the emergency room after he complained of stomach pains, prickling sensations in his legs and a desire to urinate after chewing an “energy” gum, Agence France-Presse reported.

The Italian teenager also became aggressive and agitated in school, according to a report in The Lancet, which warns about the risks of chewing stimulant gums, which contain caffeine.

The boy was panting for breath when he arrived at the emergency room and his heartbeat was 147 beats per minute. The gum had also raised his blood pressure. Doctors at the Naples Monaldi hospital kept him overnight for observation.

“Our patient admitted consuming two packets of the chewing gum, containing 320 milligrams of caffeine in four hours,” doctors at the hospital told the medical journal. “This is equivalent to about 10 cups of tea.”

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Click here to read the report in the Lancet (subscription required).