Cassia Bark Oil

Traditional Use

Primary Actions

• Warms the middle burner and dispels interior cold - Rou Gui You is used when cold obstructs the Spleen and Stomach, leading to epigastric chilliness, poor appetite, abdominal pain, or loose stool that clearly improves with warmth.
• Strengthens Stomach and Spleen Yang in aromatic form - the oil preparation is lighter and more immediately dispersing than the crude bark decoction, so it is historically associated with short-term use for cold-damp digestive discomfort, nausea from cold, and sluggish middle-jiao Qi movement.
• Expels wind and opens the surface through aromatic warmth - traditional summaries describe it as useful when exterior wind-cold or cold-damp lodges superficially while the middle burner is also weak and chilled.
• Provides a concentrated warming external preparation - topical use is traditionally directed toward cold-pattern pain, localized chill, and stiff aching areas where a penetrating cinnamon preparation is preferred over a bulky decoction.

Secondary Actions

• Rou Gui You should be understood as a preparation derived from the same source plant as Rou Gui, but in a much more concentrated aromatic form that is stronger on the nose, more irritating to tissues, and less suitable for prolonged unsupervised use.
• The alternate name Gui Pi You (桂皮油) appears in some materia medica references and reflects the overlap between cassia bark and cinnamon-bark oil terminology in trade.

Classical References

• TCM Wiki records Rou Gui You as pungent, sweet, and warm, with the actions of expelling wind, strengthening the Stomach, and warming the Spleen and Stomach.
• Traditional usage treats the oil as a preparation-state derivative of Rou Gui rather than a different medicinal species, so its core therapeutic direction remains warming, dispersing, and middle-jiao supporting.
• IDENTITY NOTE: this record is for the concentrated oil preparation 肉桂油, not the crude bark herb Rou Gui (肉桂); the two share source material but are not interchangeable gram-for-gram.