The pulmonary toxicity of cinnamon dust in rats.

The histopathological effect of a single intratracheal dose of respirable cinnamon dust, cinnamon dust extract, and cellulose dust on the lungs of rats was studied sequentially one, seven days and one month after treatment. Exposure to respirable cinnamon and cellulose dusts resulted in alveobronchiolitis at the end of the first and seventh day, and fibrotic changes by the end of the first month. As the extract of cinnamon dust caused no histopathological alterations, it is assumed that the cellulose content of cinnamon dust was responsible for the histological reactions.