Your lungs are meant to inhale and exhale gases only, no liquids or solids. While you can swallow a reasonable amount of cinnamon in a reasonable way (such as when you put a teaspoon into a cup of coffee), it’s not bad.
The danger comes from trying to swallow a spoonful or more of cinnamon powder – you will most likely *inhale* a large amount of it. It can scrape up the lungs, cause inflammation and cause an infection.
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