Also known as Fructus Psoraleae Corylifoliae, actually it refers to the seed of Psoralea pinnata. L. or Psoralea corylifolia L. (Psoralea corylifolia Linn.), which is an annual plant growing mainly in provinces of Henan, Anhui, Guangdong, Shanxi, Jiangxi and Sichuan in China. However, it isn't native to China but west Asia.

The dried psoralea seeds appear mainly as flat ellipse but sometimes shape something like a kidney, 3 to 5mm long, 2 to 4mm in diameter, 1.5mm thick, with a dimple in the middle, and dark brown rough surface with fine reticulate wrinkles and dense glandular spots. The thin pericarp is hard to be peeled off from the testa. Inside there is one kernel and a pair of cotyledon, from light brown to yellowish-brown, and rich in oil. And it has a very light sweet smell and slightly bitter and pungent taste.

The seeds of psoralea coryli folia should be collected when they are ripe in autumn, and then dried in the sun. Medicinally both the raw and the stir-fried with brine are being employed.

WHAT'S IT USED FOR? 
According to Traditional Chinese Medicine (TCM), the properties of Buguzhi are warm, bitter, and acrid. And it covers meridians of kidney pericardium, spleen, stomach, and lung.

Main functions are to tonify kidney yang, respire qi for relieving Asthma, and warm spleen for stopping diarrhea. Main uses and indications are deficient kidney yang, deficient cold in lower jiao, cold-pain in low back and knee, ED (erectile dysfunction), Nocturnal Emission, frequent micturition, enuresis, deficiency of kidney qi failing to control respiring qi, non-stop dyspnea of deficiency type, asthenia of both the spleen and kidney, chronic diarrhea, Vitiligo, alopecia areata or Hair Loss, and Psoriasis. Regular dosage is 6 to 15 grams in decoction, or in wan (teapills) and in San (powder). Externally apply appropriate amount of tinctures on the infected part.

Psoralea fruit

RELATED HERBAL FORMULAS
Thanks to its fabulous healing properties, this herb is widely used in many herbal treatments in TCM. The renowned applications are as follows, to name but a few.
(1). Si Shen Wan (Four Spirits Pill), from Zheng Zhi Zhun Sheng (Standards of Patterns and Treatments) written by Wang Ken-Tang in 1602, is mainly for the cure of fifth-watch diarrhea due to deficient cold in spleen and kidney. Other Chinese herbs are Rou Dou Kou (Nutmeg Seeds), Wu Zhu Yu (Evodia Fruit), and Wu Wei Zi (Schisandra Seed);

(2). Bu Gu Zhi Wan, from Ben Cao Gang Mu (Compendium of Materia Medica) written by Li Shizhen in the Ming Dynasty (1378~1644), is primarily for the remedy of deficiency of lower burner, heavy arms and legs, and profuse night sweat. Other healing herbs are Tu Si Zi (Chinese Dodder Seeds), Hu Tao Ren (Walnut Nut), Ru Xiang (Frankincense), Mo Yao (Myrrh), and Chen Xiang (Aloeswood);

(3). Qing’e Wan, from Tai Ping Hui Min He Ji Ju Fang (Imperial Grace Formulary of the Tai Ping Era) written by the Imperial Medical Department in 1078-1085, is formulated for low back pain caused by deficient kidney. Other medicinal herbs are Du Zhong (Eucommia Bark), Hu Tao Ren, and Da Suan (garlic).