The authors point out that cinnamon, when used sparingly, as a spice, is harmless, but when ingested in larger quantities, can be dangerous. That is partly because cinnamon is composed of cellulose fibers that, if aspirated into the lungs, neither dissolve nor biodegrade.

The authors say that although no studies of cinnamon exposure have been conducted in humans, several animal studies have shown that intratracheal exposure to cinnamon can have deleterious effects, including granulomata, interstitial fibrosis, alveolar histiocytosis, alveolar lip proteinosis, and alveolar cell hyperplasia.

Attempts to swallow even just a spoonful of dry cinnamon carry a real risk for aspiration, the authors say. At least 30 individuals who engaged in the practice have required medical attention, and people with broncho-pulmonary diseases, including asthma, may be especially prone to injury.

During 2011, the US American Association of Poison Control Centers received 51 calls related to the Cinnamon Challenge. Since then, the number of children and adolescents engaging in the practice has apparently increased dramatically: During the first 6 months of 2012, Poison Control Centers reported 178 calls related to intentional ingestion of cinnamon powder.

That surge in calls corresponds to the number of Cinnamon Challenge videos posted on social media Web sites.

More: ‘Cinnamon Challenge’ Poses Potentially Serious Health Risks