Educational information, not medical advice — ask your doctor or midwife.
Shin'i is the dried, unopened flower bud of the magnolia tree (Latin name Magnolia salicifolia). In Kampo, the traditional herbal medicine of Japan, it is the single drug reached for when the nose is blocked. It is also called Magnolia Flower Bud, and in Chinese medicine Xin Yi Hua.
People use it for a stuffy nose, a runny nose, and sinusitis (swelling and infection in the air spaces behind the face). It is rarely taken on its own. Most often it sits inside a larger Kampo formula with several other herbs.
Here is the honest verdict up front. Shin'i has a long and respected place in tradition, but good human trials of the herb by itself are missing. A long history of use is not the same as proof that something works, and that gap is stated here once so you can weigh the rest of this page with it in mind.
Nobody has shown clearly how Shin'i works in people. What follows is the current thinking, not settled fact.
The bud holds a fragrant oil. Lab work suggests parts of this oil may calm swelling in the lining of the nose, which could make the airway feel more open. Some of the herb's other compounds have damped down inflammation (swelling and irritation) in test tubes and in animals.
Those results come from dishes and rodents, not from people with blocked noses. The step from a lab bench to your sinuses is a big one, and it has not been made. Treat any mechanism you read about, here or elsewhere, as a reasonable guess.
Shin'i comes in a few shapes:
Dried whole buds, for making a decoction (a strong tea made by simmering herbs). The buds are furry, and the fine hairs can scratch the throat, so they are traditionally tied in a cloth bag before simmering.
Granules or fine powder, the usual modern Kampo form in Japan. These are premade water extracts, most often as part of a multi-herb formula rather than the single herb.
Tablets and capsules, mostly sold outside Japan.
You will most often meet it inside named formulas such as Shin'i seihai to or Kakkon to ka senkyu shin'i.
Magnolia flower bud appears in the oldest Chinese herbal writing, the Shen Nong Ben Cao Jing, roughly two thousand years old. It was classed as a herb that opens the nose and clears the head.
Japanese Kampo took it up and kept that role. By the Edo period it was a fixed part of formulas for blocked noses and long-running sinus trouble, and it still holds that spot in Japanese practice today.
Korean and Chinese medicine use the same bud, sometimes from related magnolia species.
See a doctor if your blocked nose lasts more than ten days, or gets better and then worse again.
Get medical help the same day for a fever above 38.5C with facial pain, swelling or redness around an eye, a change in your vision, a severe headache, a stiff neck, or confusion. These can be signs that a sinus infection is spreading.
Get emergency help for a rash, swelling of the face, lips or tongue, or trouble breathing after taking it. Also call your doctor if your heart races or pounds after a Kampo mix that contains Ephedra.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
The published evidence for Shin'i is weak or absent. That usually means no controlled trial has tested it, not that a trial found it ineffective — the two are different, and we grade only what has been published.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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