Obtained by steam distillation of bark. Pale to dark yellow oil with strong warm spicy and rich body odour.
Main Components: cinnamaldehyde (55-75%), eugenol (5-18%), linalool.
Actions*: antiseptic, antifungal, analgesic, anaesthetic, cardiac, stimulant, stomachic, insecticide.
Applications*: one of the strongest antibacterial e.o., useful in contagious diseases, acute bacterial infections, gastrointestinal stimulant, dyspepsia, colitis, diarrhoea, nausea, aches and chills, rheumatism, depression.
Safety data: severe dermal irritant and sensitizer (especially cinnamaldehyde), contraindicated during pregnancy. Cinnamaldehyde causes serious cardiovascular toxicity in mice leading to pulmonary congestion and death. Eugenol is hepatotoxic and damages mucosal epithelium.

Obtained by steam distillation of leaves. Yellow to brownish oil with warm spicy but rather harsh odour, similar to the e.o. of clove leaves.
Main Components: eugenol (70-90%), benzyl benzoate, cinnamaldehyde.
Actions*: analgesic, antiseptic, antifungal, anaesthetic, cardiac, stimulant, stomachic, insecticide.
Applications*: one of the strongest antibacterial e.o., useful in acute bacterial infections, aches and chills, rheumatism, depression.
Safety data: mild dermal irritant and sensitizer, contraindicated during pregnancy, hepatotoxic.

Summarizing the safety: both e.o. are toxic not only for bacteria but for humans as well. Cinnamon bark oil is stronger skin irritant and sensitizer (it is easier to develop allergy) while the leaf variety is more harmful to liver. Please do not ingest them, as suggested by some young enthusiasts and choose safer e.o. (peppermint, for example) to cure your upset stomach and such.