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Herb library · Herb · Magnolia officinalis

Magnolia bark (houpo)

The thick, aromatic bark of a Chinese magnolia, a staple of Chinese digestive formulas and today an ingredient in chewing gums and stress blends. A chewing gum with its extract reduced gum bleeding in one trial; its best-known supplement blends are mixtures.

Traditional use

Stuart's 1911 English guide to the Chinese materia medica, following Li Shizhen's Bencao Gangmu, records that the tree was cultivated in the upper Yangtze provinces for its bark, a large article of commerce, and that the aromatic, bitter bark was prescribed as a tonic, stomachic, quieting and anthelmintic remedy for diarrheas, flatulence, heartburn and irregular periods. He warns that much of the bark in the shops was tasteless, probably inert, and in some places the bark of another tree. Houpo remains a common ingredient of Chinese formulas.

What studies show

  • Limited

    Gums and plaque: in a 30-day randomized trial in 120 adults at high risk of tooth decay, a sugar-free gum with magnolia bark extract lowered decay-causing bacteria in saliva, plaque acidity and gum bleeding compared with xylitol gum and plain gum.

  • Insufficient

    Stress and weight: the trials behind these uses tested a blend of magnolia and phellodendron bark, not magnolia alone.

Be careful of

Cautions

  • AllergyMagnolia bark extract in skin and cosmetic products has caused allergic contact dermatitis, including rashes that left dark patches on the skin.
  • NoteStuart already warned in 1911 that much of the bark sold was another tree's. Some Chinese herbal products have been contaminated with heavy metals, pesticides or other herbs, according to NCCIH; buy from makers that test.
  • InteractionIt is sold in blends for stress; what it does to other medicines has not been studied. If you take sleep medicines or sedatives, ask a clinician or pharmacist first.
  • PregnancyNo safety information for pregnancy or breastfeeding was found; avoid it then.
  • Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.

From the old books

What herbals and dispensaries of the past printed. History, in their words.

“The taste of the true bark is aromatic and bitter, but some of the drug found in the shops is almost tasteless, and is probably inert.”
G. A. Stuart, Chinese Materia Medica: Vegetable Kingdom (1911), p. 255. See the page of Chinese Materia Medica: Vegetable Kingdom, p. 255 (opens in a new tab) · Read the full passage from Chinese Materia Medica: Vegetable Kingdom, p. 255

Sources

  1. Effect of a sugar-free chewing gum containing magnolia bark extract on different variables related to caries and gingivitis: a randomized controlled intervention trial (Caries Res, 2011) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  2. Effect of a proprietary Magnolia and Phellodendron extract on stress levels in healthy women: a pilot, double-blind, placebo-controlled clinical trial (Nutr J, 2008) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  3. Allergic contact dermatitis of the face caused by Magnolia officinalis bark extract (Contact Dermatitis, 2016) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  4. Hyperpigmentation as a manifestation of contact allergy to Magnolia officinalis bark extract (Contact Dermatitis, 2021) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  5. Vulvar allergic contact dermatitis caused by Magnolia officinalis bark extract (Contact Dermatitis, 2022) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
  6. Traditional Chinese Medicine: What You Need To Know (opens in a new tab) · NCCIH · read September 25, 2026

Reviewed September 25, 2026.