Poria cocos is wildly distributed in China, and mainly produced in Hubei, Yunnan, Anhui, and Guizhou provinces of China^[1] 馬傳貴，張志秀. 茯苓的中醫藥研究現狀與臨床治療進展[J].食用菌，2020，42（04）：4-8+19..

Poria cocos is a saprophytic fungus, a type of mushroom used in Chinese medicine for a long time. Natural Poria cocos grows on the roots of pine trees, and is generally found in the slightly acidic sandy loam at an altitude of 500-1000 meters. Slopes with dry air and sufficient sunlight are more conducive to the growth of Poria cocos.

The growth of Poria cocos requires a large amount of nutrients from the pine trees, so pine trees are the main materials for cultivating Poria cocos^[2] 王克勤， 茯苓等三種中藥材規範化種植研究. 湖北省，湖北省中醫藥研究院，2002-11-10.. The preparation process for Poria cocos cultivation, such as materials preparation and site selection, generally starts in the late autumn and early winter of the previous year, and the plantation of Poria cocos using the method of cut-log cultivation will start from before 4th April until the summer solstice in the subsequent year ^[3] 鐘志. 茯苓的種植技術[J].農家之友，2011（12）：13..

The shape of Poria cocos is very similar to the sweet potatoes we eat in our daily life. The outer skin of Poria cocos is thin and rough with obvious shrinkage texture, and the color is brown to dark brown.

Poria cocos sold in the market is often peeled and cut into slices of different sizes, or peeled and cut into cubes. It is usually white, light red or light brown in color.

Figure 1: Poria cocos that grows in the nature.

Figure 2: Blocks of Poria cocos after processing.

Poria cocos was first recorded in “The Divine Farmer’s Classic of Materia Medica, Shen Nong Bencao Jing” and was listed as a top grade supplement. It was named Poria cocos based on its shape that resembling a rabbit.

“Wu Shi Er Bing Fang” (Recipes for Fifty-Two Ailments) was the earliest ancient book to record the medicinal effects of Poria cocos. At that time, Poria cocos was mainly used to treat ‘gan sao’ (a kind of cutaneous pruritus, but there are no wounds nor secretions on the skin after scratching)^[4] 張超偉，張鈺，蘇珊，程磊. 茯苓類藥材本草學、化學成分和藥理作用研究進展[J].湖北農業科學，2021，60（02）：9-14+19..

In the Tang Dynasty, taking Poria cocos became a trend. In “Qian jin yi fang” (Supplement to the Essential Prescriptions Worth a Thousand Gold), a traditional Chinese medicine prescription for Poria cocos, the Fuling prescription was specially developed ^[5] 唐·孫思邈 . 備急千金要方校釋[M]. 北京：人民衛生出版社，1998. Because Poria cocos has a wide range of effects, its usage is not affected by the seasons, and it can be used in combination with various drugs, hence, Poria cocos has the reputation of “the magical medicine of the four seasons”^[6] 唐·甄 權 .藥性論[M].合肥：皖南醫學院科研科，1983.38..

Poria cocos can be purchased in the open market and is widely used in the pharmaceutical preparations in Japan, Thailand and some other Asian countries^[7] Sun, Yichun. "Biological activities and potential health benefits of polysaccharides from Poria cocos and their derivatives." International Journal of Biological Macromolecules 68 (2014): 131-134.. In Japan, Poria cocos is being used as a diuretic, sedative, and nourishing herb with significant effects^[8] Ríos, José-Luis. "Chemical constituents and pharmacological properties of Poria cocos." Planta medica 77.07 (2011): 681-691..

Poria cocos is reputed as a product of “souls resurrection, no hunger and prolonged life” in “The Divine Farmer’s Classic of Materia Medica, Shen Nong Bencao Jing”. As a famous traditional Chinese medicine with a rich yield, Poria cocos has a variety of effective components that make it has the effect of anti-tumor, modulating gut microbiota dysbiosis, protecting the liver, boosting immunity, diuresis, and maintaining beauty ^[9] Ji HJ, Kang N, Chen T, Lv L, Ma XX, Wang FY, Tang XD. Shen-ling-bai-zhu-san, a spleen-tonifying Chinese herbal formula, alleviates lactose-induced chronic diarrhea in rats. J Ethnopharmacol. 2019 Mar 1; 231:355-362. ^[10] Wu R, Zhao D, An R, Wang Z, Li Y, Shi B, Ni Q. Linggui Zhugan Formula Improves Glucose and Lipid Levels and Alters Gut Microbiota in High-Fat Diet-Induced Diabetic Mice. Front Physiol. 2019 Jul 23; 10:918. ^[11] Zhang Y, Tang K, Deng Y, Chen R, Liang S, Xie H, He Y, Chen Y, Yang Q. Effects of shenling baizhu powder herbal formula on intestinal microbiota in high-fat diet-induced NAFLD rats. Biomed Pharmacother. 2018 Jun; 102:1025-1036..

1. Polysaccharides

Poria cocos contains a large quantity of polysaccharides^[12] Chen X, Zhang L, Cheung PC. Immunopotentiation and anti-tumor activity of carboxymethylated-sulfated beta-(1-->3)-d-glucan from Poria cocos. Int Immunopharmacol. 2010 Apr; 10(4):398-405., which accounts for about 70%-90% of the total mass of Poria cocos. Poria cocos has the function of strengthening the human body and improving body immunity because of its polysaccharides content^[12] Chen X, Zhang L, Cheung PC. Immunopotentiation and anti-tumor activity of carboxymethylated-sulfated beta-(1-->3)-d-glucan from Poria cocos. Int Immunopharmacol. 2010 Apr; 10(4):398-405.. Polysaccharides are easily absorbed by the human body. They are anti-tumor and liver-protecting food, and are very suitable for people who are weak and bedridden for a long time.

2. Triterpenes

The content of triterpenes in Poria cocos is very high, and 57 kinds of triterpenes have been detected in Poria cocos. Triterpenes are predominantly extracted from the outer skin and the sclerotium of the Poria cocos^[13] UKIYA M， AKIHISA T， TOKUDA H， et al. Inhibition of  tumor-promoting effects by poricoic acids G and H and Other lanostane-type triterpenes and cytotoxic activity of poricoic acids A and G from Poria cocos[J]. Journal of  Natural Products, 2002, 65（4）: 462-465.. Triterpenes have  a good anti-inflammatory effect^[14] Cuellar MJ, Giner RM, Recio MC, Just MJ, Mañez S, Rios JL. Effect of the basidiomycete Poria cocos on experimental dermatitis and other inflammatory conditions. Chem Pharm Bull (Tokyo). 1997 Mar; 45(3):492-4.. In our daily life, triterpenes from Poria cocos can inhibit the formation of ulcers. Besides, poriatin, a kind of triterpenes in Poria cocos makes it have a diuretic effect.

3. Amino Acids and Trace Minerals

The amino acid and micro-minerals in Poria cocos have many functions^[15] Richard Evans Schultes. Oriental Materia Medica: A Concise Guide[J]. Economic Botany. 1988 (1), such as enhancing the immune function of the human body, improving the hematopoietic function of the bone marrow and maintaining beauty.

The processing method recorded in the Chinese Pharmacopoeia 2020 edition^[16] 國家藥典委員會 . 中華人民共和國藥典[S]. 北京; 中國醫藥科技出版社，2020，251. that “The whole Poria cocos is taken, soaked, washed, steamed for a little while after moistening, peeled off the skin in time, cut into chunks or thick slices, and dried”. At present, the content of the pachymic acid and polysaccharides in the Poria cocos is used as a key attribute to determine the best processing technology^[17] 崔鶴蓉，王睿林，郭文博，王鵬龍，馬濤，李瑞生，賈天柱，何塞·路易士·里奧斯，張振秋，雷海民. 茯苓的化學成分、藥理作用及臨床應用研究進展[J].西北藥學雜誌，2019，34（05）：694-700..

Poria cocos is a commonly used traditional Chinese herb in the medicine and food homology. In “The Divine Farmer’s Classic of Materia Medica, Shen Nong Bencao Jing”, Poria cocos is listed as a top grade herb in health preservation, and it can prolong life after long-term ingestion. Poria cocos is mild in nature and tasty, which has often been made into dishes and served at the dining table of ordinary people, such as Poria cocos cake, Poria cocos cookies and Poria cocos wine, etc. The National Health Commission of China has included Poria cocos in the list of medicine and food homology. Poria cocos has also been included in the Japanese Pharmacopoeia and the European Pharmacopoeia. Through database searching, it is found that there were no reports on the toxicity of Poria cocos in the latest research.

Though Poria cocos is a traditional Chinese medicine in the medicine and food homology, there is no clinical data available on the single prescription of Poria cocos. 92 clinical studies of various compound prescriptions using Poria cocos as the key traditional Chinese medicine, involving 3778 tumor patients, found that the compound prescriptions can effectively regulate immunity, increase the tolerance of cancer patients to the side effects of chemotherapy, help patients complete the course of chemotherapy, reduce swelling, increase the total number of white blood cells, and reduce the side effects on the gastrointestinal tract^[18] Lv C, Shi C, Li L, Wen X, Xian CJ. Chinese herbal medicines in the prevention and treatment of chemotherapy-induced nausea and vomiting. Curr Opin Support Palliat Care. 2018; 12(2):174-180. doi: 10.1097/SPC.0000000000000348. PMID: 29697417..