Prepared Magnolia Bark Classic Formulas … Natural Herb Library

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Moves Qi and relieves focal distention ... Zhi Hou Po is used when fullness, bloating, epigastric oppression, abdominal pain, or food stagnation are driven by middle-burner Qi blockage.
Dries Dampness and harmonizes the Spleen and Stomach ... it remains a standard choice when damp obstruction leads to poor appetite, nausea, greasy coating, loose stool, or a heavy obstructed digestive sensation.
Descends rebellious Qi and transforms phlegm ... the prepared bark is used for cough, wheezing, chest congestion, and plum-pit Qi when phlegm and constrained descent bind the chest and throat.
Promotes downward movement in the intestines ... especially when constipation coexists with distention, pressure, and stubborn Qi stagnation rather than simple dryness.

Ban Xia Hou Pu Tang (半夏厚朴汤) ... classic Jin Gui Yao Lue formula using Hou Pu for plum-pit Qi, throat obstruction, nausea, and emotional constraint with phlegm.
Ping Wei San (平胃散) ... dampness-transforming formula in which Hou Pu moves Qi, dries damp, and relieves epigastric and abdominal fullness.
Hou Pu San Wu Tang (厚朴三物汤) ... abdominal fullness, pain, and constipation driven by pronounced Qi stagnation.
Ma Zi Ren Wan (麻子仁丸) ... includes Hou Pu to move constrained Qi and help bowel movement when distention accompanies dry constipation.

Classical materia medica consistently describe Hou Pu as bitter, acrid, warm, and aromatic, entering the Spleen and Stomach to move Qi, dry dampness, and direct stagnation downward.
Formula tradition uses processed and unprocessed Hou Pu in overlapping ways, but the prepared form is commonly preferred when a cleaner and slightly moderated interior use is desired.
PREPARATION NOTE: Zhi Hou Po is not a distinct species or a different medicinal family ... it is the clinically prepared bark form of Magnolia officinalis used to make the crude bark easier to handle and prescribe.