Hou Po (Officinal Magnolia Bark)

Name

Hou Po (Cortex Magnoliae Officinalis), recorded in the Shennong Bencao Jing (Shennong's Herbal)

Source and quality

Origin

The dried bark, or the bark of the branch or root, of Magnolia officinalis Rehd. et Wils. or M. officinalis Rehd. et Wils. var. biloba Rehd. et Wils., family Magnoliaceae.

Where it is grown

Sichuan and Hubei provinces, and elsewhere in China.

Harvest

Collected from April to June.

Smell and taste

Fragrant, acrid and slightly bitter.

Better grade

Thick bark with a smooth surface, heavy and oily, purple-brown in the endothecium, with a lustrous crystalline surface and a strong fragrance.

Processing

Cut into pieces and prepared with ginger juice.

Nature and action

Bitter, acrid and warm; enters the Spleen, Stomach, Lung and large intestine channels. Dries dampness, moves qi and relieves dyspnea.

When it is used

Damp obstruction of the middle jiao

Hou Po is bitter and acrid: it not only dries damp turbidity but also moves qi and relieves distention. Where damp obstructs the middle jiao and qi movement is disturbed, with gastric and abdominal distention, poor appetite, nausea and vomiting, it is usually combined with herbs that dry dampness and move qi, such as Cang Zhu and Chen Pi in Ping Wei San from Tai Ping Hui Min He Ji Ju Fang.

Qi stagnation of the Stomach and intestines

Hou Po is fragrant, and is the essential herb for moving qi and relieving distention.

For constipation with gastric and abdominal distending pain due to heat retention, it is combined with purgative and heat-clearing herbs, such as Da Huang and Mang Xiao in Da Cheng Qi Tang from Shang Han Lun.

Where food stagnation disturbs qi movement, with gastric and abdominal distending pain, belching and acid regurgitation, it is combined with digestants, such as Zhi Shi and Mai Ya in Zhi Shi Xiao Pi Wan from Lan Shi Mi Cang.

Dyspnea and cough from adverse rise of qi

Hou Po dries dampness, resolves phlegm, drives qi downward and relieves dyspnea. Where phlegm and dampness obstruct the interior so that lung qi rises adversely, with cough, dyspnea and chest stuffiness, it is combined with herbs that dry dampness, resolve phlegm, drive qi downward and relieve dyspnea, such as Zi Su Zi, Chen Pi and Ban Xia in Su Zi Jiang Qi Tang from Tai Ping Hui Min He Ji Ju Fang.

For chest stuffiness, dyspnea and wheezing due to phlegm retained in the throat, with restlessness caused by cold fluid transforming into heat, it is combined with herbs that clear the lung and relieve dyspnea, such as Ma Huang, Shi Gao and Xing Ren in Hou Po Ma Huang Tang from Jin Gui Yao Lue.

For dyspnea and cough brought on by renewed invasion of wind-cold, it is combined with herbs that induce sweating to release the exterior and open the lung to relieve dyspnea, such as Gui Zhi and Xing Ren in Gui Zhi Jia Hou Po Xing Zi Tang from Shang Han Lun.

Plum-stone syndrome

Its actions of drying dampness, resolving phlegm, driving qi downward and soothing the middle jiao also apply to plum-stone syndrome, where phlegm and qi combine. It is combined with herbs that resolve phlegm and move qi, such as Ban Xia, Fu Ling, Zi Su and Sheng Jiang in Ban Xia Hou Po Tang from Jin Gui Yao Lue.

Dose

Decoct 3~10 g, or grind into powder for use in pills and powder.

Cautions

Use with caution in patterns of qi deficiency with fluid consumption, and in pregnancy.