What it is:
This herb is the tender twigs of Cin- namomum cassia Presl (family Lauraceae), produced chiefly in the provinces of Guangxi, Guangdong and Yunnan. The twigs are collected in spring or summer, dried in sunlight or in shade, sliced and used unprepared.

Property:
Pungent and bitter in flavour, warm in property, acting on the lung, heart and urinary bladder channels.

Effects:
Dispelling pathogenic factors from the exterior of the body by diaphoresis, warming the channels to relieve pain, and reinforcing yang to promote the flow of qi.

Used for:
1. Affection by wind-cold exopatho- gens with such sym- ptoms and signs as headache,fever,aver- sion to cold, etc. For exterior syndrome of deficiency type with spontaneous sweating, it is used together with white peony root, fresh ginger, Chinese date, and liquorice, known as Cinnamon Twig Decoction (Guizhi Tang); for exterior syndrome of excess type with no sweat, it is used with ephedra and others, known as Ephedra Decoction ( Mahuang Tang).

2. Arthralgia due to wind-cold -dampness manifested as aching joints of the shoulders and limbs. For the syn- drome with wind- dampness in the exterior and with deficiency of exterior-yang, it is used with the lateral root of aconite, as in Decoction of Cin- namon Twig and Aco- nite ( Guizhi Fuzi Tang). In cases of blood-arthralgia and numbness due to deficiency of ying and wei, it can be used with astragalus root, peony root and other herbs, as in Decoction of Five herbs Including Astragalus and Cin- namon (Huangqi Gui zhi Wuwu Tang).

3. For blood stasis due to patho- genic cold in the blood of women with manifestations of irregular menstru- ation, amenorrheal abdominal pain and mass in the abdomen, the herb is often sued in combination with herbs for pro- moting blood circu- lation and restoring menstrual flow, such as Chinese angelica root, peony root, Chuanxiong rhizome, peach kernel and mout an bark, as in Deco- ction for Warming Channels( Wenjing Tang) and Cinnamon Twig and Poria Pill (Guizhi Fuling Wan).

4. For cold syn- drome of deficiency type in the middle- jiao manifested as vague pain in the epigastric region which can be ame- liorated by warmth and pressing, it is often prescribed with white peony root, malt sugar, astragalus root and others, as in Decoc- tion of Astragalus for Tonifying Middle- jiao (Huangqi Jian zhong Tang).

5. For stagnation of yang-qi and reten- tion of water in the body due to defi- ciency of the heart and spleen with manifestation of cold feeling in the back, hypochondriac disten- sion, cough, dyspnea and vertigo, it is often used with poria and white atracty- lodes rhizome, as in Decoction of Poria, Cinnamon Twig, Atrac- tylodes and Liquorice (Ling Gui Zhu Gan Tang). For stagnation of qi in the urinary bladder manifested as difficulty in uri- nation and edema, it is often used with poria, umbellate porefungus and water- plantain tuber, as in Powder of Five Herbs Including poria (Wu Ling San).

6. For obstruction of qi in the chest and chest pain, it is often used with immature bitter orange, trichosanthes fruit and macrostem onion,as in Decoction of Immature Bitter Orange, Macrostem Onion and Cinnamon Twigs (Zhishi Xiebai Guizhi Tang). For palpitation and slow pulse with irregular intervals, it is usually used with stir- baked liquorice, ginseng and donkeyhide gelatin, as in Decoction of Prepared Liquorice(Zhi Gancao Tang).

Dosage and admi- nistration: 3-10g, decoction in water for an oral dose. Precautions: Since this herb is pungent and warm and can bring about heat to damage yin and cause blood disorder, it is contraindicated for epidemic febrile diseases and syndrome of yin deficiency accompanied with hyperactivity of yang, throat prob- lems,blood disorders, or dry mouth and tongue due to chronic internal fire. It should be used cautiously for pregnant women or patients with menorrhagia.