Hou Po (Magnolia Bark)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Hou Po?

  About 3–9 g, up to 10 g, in decoction. Materia medica sources give slightly different ends of the same range (3–9 g / 3–10 g); like other aromatic qi-regulating herbs it is often added later in the decoction so its volatile constituents are not lost to prolonged boiling.

  • Raw (shēng) Hou Po — favored when stronger phlegm-drying and qi-descending action is the goal.
  • Ginger-processed (jiáng zhí) Hou Po — the more common prepared form; ginger-curing tempers Hou Po’s mucous-membrane irritation and is preferred for oral use, especially for nausea/vomiting.

  Source: Sacred Lotus reference notes; Bensky, Materia Medica (3rd ed.); Chen & Chen, Chinese Herbal Medicine: Materia Medica. Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Hou Po?

  Use with caution in pregnancy and in cases of qi deficiency. As a warm, drying, qi-moving and qi-descending herb, Hou Po’s draining action is not well suited to deficiency patterns without accompanying fullness, and its warming, moving nature calls for caution during pregnancy.

  • Sourcing (reference note) — Magnolia officinalis is listed by the IUCN as a threatened species, reflecting sustained bark-harvesting pressure for medicinal use. Noted here as a neutral sourcing/conservation reference fact, not a safety concern.

  Source: Sacred Lotus reference notes; IUCN Red List (Magnolia officinalis). Reference only, not medical advice.

Chinese Herb Toxicity & Overdose

• Low, per available safety data. A 2018 pharmacological safety/toxicology review of magnolol and honokiol (Hou Po’s principal neolignans) found no mutagenic or genotoxic signal for concentrated magnolia bark extract, established a no-observed-adverse-effect level above 240 mg/kg body weight/day in a subchronic animal study, and noted that human intervention trials using concentrated extract for up to one year reported no adverse effects; food-safety authorities have generally considered magnolol and honokiol safe at studied doses.

  Source: PMID 29925102 (Planta Medica, 2018, safety/toxicology review). Reference note, not a safety guarantee.

Herb-Drug Interactions

• Caution with antiplatelet and anticoagulant medication. Magnolol, one of Hou Po’s principal active constituents, has documented antiplatelet activity — laboratory research shows it inhibits platelet aggregation via a PPAR-β/γ-mediated pathway — so practitioner awareness is reasonable for patients taking aspirin, clopidogrel, dipyridamole, heparin, warfarin, or enoxaparin. This reflects a plausible pharmacological interaction from preclinical mechanism studies, not a confirmed clinical interaction case.

  Source: PMID 22750553 (Biochemical Pharmacology, 2012). Reference note for practitioner awareness, not a demonstrated clinical interaction.

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on Hou Po (Magnolia officinalis)?

  Yes — laboratory studies support the traditional digestive actions, and the classic Hou Po formula Ban Xia Hou Po Tang has clinical-trial evidence for functional dyspepsia, swallowing/globus symptoms, and depression. Hou Po’s two principal bioactive neolignans, magnolol and honokiol, are the focus of most modern pharmacology.

  • Gastrointestinal motility (mechanistic) — magnolol dose-dependently inhibited contractions of guinea-pig distal colon in vitro, acting via calcium-channel blockade and reduced calcium release; separately, magnolol and honokiol improved gastric emptying and intestinal propulsive activity in mice. Laboratory research consistent with Hou Po’s traditional qi-moving/digestive indications.
  • Ban Xia Hou Po Tang (Hangekobokuto) for functional dyspepsia — a clinical study found the formula reduced bowel gas volume and improved bloating, abdominal pain, and constipation in patients with functional dyspepsia.
  • Ban Xia Hou Po Tang for swallowing function — in elderly patients with a history of aspiration pneumonia, four weeks of the formula significantly shortened swallowing-reflex latency and raised salivary substance P, read by the authors as support for its traditional “plum-pit throat” (globus) indication and airway-protective potential.
  • Ban Xia Hou Po Tang for depression — a 2023 systematic review and meta-analysis of 15 randomized controlled trials (1,714 participants) found the formula comparable to standard antidepressants on depression rating scales when used alone, with added benefit in combination and a favorable safety profile alone; the authors caution that evidence quality ranged from very low to moderate.
  • Neuropharmacology (mechanistic) — a 2023 review of magnolol and honokiol summarizes CNS-active signaling pathways (including GABAergic mechanisms) proposed to underlie their traditional calming/sedative-adjacent reputation; preclinical/mechanistic evidence, not a clinical claim for Hou Po itself.

  Overall: strong mechanistic and formula-level clinical support for the traditional digestive/phlegm indications; the “plum-pit throat” (globus) and mood-related clinical trials are formula-level evidence (Ban Xia Hou Po Tang as a whole), not isolated-herb evidence for Hou Po alone.

  Sources: PMID 16595919 (Biol Pharm Bull, 2006); PMID 16038044 (World J Gastroenterol, 2005); PMID 18955239 (Evid Based Complement Alternat Med, 2009); PMID 10374248 (Phytomedicine, 1999); PMID 37224584 (Complement Ther Clin Pract, 2023); PMID 35196977 (Curr Mol Pharmacol, 2023). Research context, not a therapeutic claim.

Chinese Herb Notes

• Is Hou Po the same as Xin Yi Hua, or how does it compare to Cang Zhu?

  No — Hou Po is the dried bark of Magnolia officinalis, while Xin Yi Hua is the unopened flower bud of a different magnolia species; the two share a genus but not an action. Xin Yi Hua is an aromatic herb that opens the nasal passages (sinus congestion, nasal obstruction); Hou Po works on qi stagnation and dampness in the middle burner and has no nasal/sinus indication.

  • Hou Po vs. Cang Zhu — both are aromatic, dampness-transforming herbs and are frequently paired (as in Ping Wei San), but Hou Po stands out for its ability to relieve fullness and accumulation, including qi-stagnation constipation, where Cang Zhu does not.

  Common combinations, grounded in the Sacred Lotus formula database:

  • Ping Wei San — paired with Cang Zhu, Chen Pi, and Gan Cao as the classic formula for a damp-encumbered Spleen/Stomach (fullness, poor appetite, greasy tongue coat).
  • Huo Xiang Zheng Qi San and Xiang Ru San — release the exterior and transform dampness in summer-heat/damp patterns with digestive upset.
  • Ban Xia Hou Po Tang — with Ban Xia, Fu Ling, Sheng Jiang, and Zi Su Ye, the classic formula for “plum-pit qi” (globus, a subjective lump in the throat from phlegm-qi constraint); known in Japan as Hangekobokuto, it has been formally studied for swallowing function and functional dyspepsia (see research).
  • Da Cheng Qi Tang, Xiao Cheng Qi Tang, Huang Long Tang, and Ma Zi Ren Wan — purgative formulas that use Hou Po to relieve the qi-stagnation abdominal fullness accompanying constipation.
  • Su Zi Jiang Qi Tang — descends qi and transforms phlegm for cough/wheezing with copious sputum.
  • Zhi Shi Xiao Pi Wan, Shi Pi Yin, Zhong Man Fen Xiao Wan, Lian Po Yin, and Hou Po Wen Zhong Tang — further Spleen/Stomach formulas built around Hou Po’s qi-moving, damp-drying, fullness-relieving action.

  Source: Sacred Lotus formula database (formula–herb composition records); Bensky, Materia Medica (3rd ed.).