Also known as the Pericarpium citri reticulatae, it refers to the dried peels of Citrus reticulata Blanco and its cultivars, one type of rutaceous plants. In China, it mainly grows in Guangdong, Fujian, Sichuan, Zhejiang, Jiangxi and other provinces. The best timing for harvest is when autumn changes into winter. At that time the fruits are ripe enough. Next, dry them in the sun or beside a fire. As far as the quality concerned, the older the better. That is also the reason why it is being called Chen Pi, which translates literally as "the old peels". And because the product from Xinhui is the best in quality, it is often called Xinhui Pi or Guang Chen Pi. Normally it is cut into shreds before the serving, in the raw form usually.

WHAT'S TANGERINE PEEL USED FOR?
This herb is deemed as acrid, aromatic, bitter, and warm in nature by Traditional Chinese Medicine (TCM). It covers at least three meridians – lung, stomach, and spleen. Its principal functions are to regulate qi-flowing for strengthening spleen and remove dampness to reduce phlegm. Its basic indications and uses include fullness and distention in chest and stomach duct, reduced appetite due to vomiting and Diarrhea, and excessive phlegm induced cough. Normal dosage is from 3 to 9 grams, in decoction usually.

Citrus Peel

CHEMICAL COMPOSITION
Modern medicine studies have revealed that citrus reticulata peel contains 1.9% to 3.5% volatile oil. The main components include Limonene, α-Thujene, α-Pinene, β-Pinene, β-Myrcene, Sabine-ne, Octanal, α-Phellandrene, α-Terpinene, p-Cymene, Linalool, Thymol, Citronellal, Hesperidin, Neohesperidin, Tangeretin, β-Sitosterol, Synephrine, and so on.

MAIN CHINESE HERBAL FORMULAS RELATED WITH TANGERINE PEEL
1) Ping Wei San
Ping Wei San is from Tai Ping Hui Min He Ji Ju Fang (Formulas of the Peaceful Benevolent Dispensary). It is a famous formula for the stagnation of spleen and stomach Qi, which mainly manifests abdominal distention and pain, vomiting, and diarrhea. Other main herbs are Cang Zhu (Atractylodes) and Hou Po (Magnolia Bark).

2) Bao He Wan
Bao He Wan is from Dan Xi Xin Fa (Dan Xi's Heart Methods of Treatment). This is a prescription for food retention, Qi stagnation, and abdominal pain and distention. Other primary herbs include Shan Zha (Hawthorn Fruit) and Shen Qu (Medicated Leaven).

3) Huo Xiang Zheng Qi San
Huo Xiang Zheng Qi San is from Formulas of the Peaceful Benevolent Dispensary. This is a formula that is used for exterior syndrome combined with endogenous damp stagnation, such as abdominal pain, vomiting, and diarrhea. Other principal herbs are Huo Xiang (Patchouli) and Zi Su Ye (Perilla Leaf).