Cassia Bark Oil — Safety & Interactions
Rou Gui You · Oleum Cinnamomi
Use with caution. Practitioner review recommended before use.
Contraindications
- Known cinnamon or cassia hypersensitivity
- Undiluted application to damaged skin or mucous membranes
- Marked internal Heat or Yin-deficiency heat patterns
Cautions
- Cassia bark oil is more irritating and sensitizing than the crude bark herb and should generally be diluted before topical use
- Some cinnamon products contain enough coumarin to raise hepatotoxicity concerns, especially with heavy or prolonged intake
- Gastrointestinal upset, burning sensations, and allergic skin reactions are possible with concentrated cinnamon oils
Drug Interactions
| Drug Class / Substrate | Mechanism | Severity | Source |
|---|---|---|---|
| CYP450 substrate drugs | Preclinical studies suggest cinnamon inhibits CYP2A6, CYP2C9, CYP2D, and CYP3A4 and may increase the risk of side effects from drugs metabolized by these enzymes | Moderate | Memorial Sloan Kettering Integrative Medicine - Cinnamon |
| Statins | Concurrent use has been associated with hepatitis in a case report | Moderate | Memorial Sloan Kettering Integrative Medicine - Cinnamon |
| Pioglitazone | Animal studies suggest cinnamon can increase pioglitazone bioavailability | Moderate | Memorial Sloan Kettering Integrative Medicine - Cinnamon |
This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before using herbal medicines, especially if you take prescription medications.