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Traditional Chinese medicine

Radish seed (lai fu zi)Raphanus sativus

The seed of the garden radish, a food-stagnation herb in Bao He Wan; a review found no human gut trials, and a cell study suggests it blocks ginseng absorption.

Botanical name
Raphanus sativus
Part used
dried ripe seed, usually stir-baked
Also called
pinyin Lai fu zi (莱菔子); Radish seed, Raphani semen, Semen Raphani
Used in
Traditional Chinese medicine
Taken for
Bloating, Indigestion, Constipation
Sold as
whole seed, powder, pills in formulas, decoction

What is meant by radish seed (lai fu zi)

Radish seed is the dried, ripe seed of Raphanus sativus L., the garden radish, a member of the mustard family. In Chinese medicine it is lai fu zi (the Latin name is Raphani Semen), and a comprehensive review describes it as long used for food dyspeptic retention, distending pain in the stomach and abdomen, constipation, diarrhea and dysentery, as well as for cough with phlegm. The Pharmacopoeia of the PRC version of Bao He Wan calls for it stir-baked.

Its chemistry is that of the mustard family: the review lists glucosinolates and sulfur-containing derivatives, phenylpropanoid sucrose esters, flavone glycosides, alkaloids, terpenoids, steroids and oligosaccharides, and notes that the glucosinolates can be turned into isothiocyanates by the plant’s enzyme or by gut bacteria. Radish seed is one of seven or eight ingredients in Bao He Wan, the classical pill for what the tradition calls food stagnation, and it is not the same as the radish sprout or the root eaten as a vegetable.

In the traditions

Traditional Chinese medicine (about TCM)

Lai fu zi is classed in the Chinese materia medica as pungent and sweet and neutral, entering the spleen, stomach and lung channels. The tradition says it reduces food accumulation and directs qi downward, and uses it for what the texts describe as fullness and distension of the abdomen, belching, acid regurgitation and poor appetite from food that has not moved on, as well as phlegm and cough. In Bao He Wan it works with hawthorn, shen qu, pinellia, poria, tangerine peel and forsythia against a food accumulation syndrome that the texts attribute to improper or excessive diet. The tradition also holds that it opposes ginseng, so that the two are not combined; a laboratory paper below frames its own result as an antagonistic mechanism against ginseng. These are the tradition’s own classifications and not findings about the body.

What the plant contains

The seed contains glucosinolates and their breakdown products, isothiocyanates, along with sulfur compounds, phenylpropanoid sucrose esters, flavone glycosides and alkaloids. A comprehensive review ascribes to the seed in laboratory and animal work effects on metabolic disease, inflammation, bacteria, blood pressure and bone, and says the material basis and mechanisms of the traditional digestive use need further study. These are preclinical findings.

What has been tested in people

We found no human trial of radish seed alone for any gut outcome, and no published human trial with results of Bao He Wan in the sources we searched. A review lists the traditional digestive uses and the laboratory pharmacology and ends by calling for study of the material basis of the traditional effects.

The nearest data are animal: in 30 young mice made to have diarrhea by a high-fat, high-protein diet plus oil, a Bao He pill decoction (containing 3 g of radish seed in a 51 g prescription) at 6.63 g per kg a day for 3 days restored the activity of lactase and the microbiota of the intestinal mucosa (P below 0.01 for each against the untreated model). This is a mouse study of the whole formula, with a dose that is not a human dose.

One cell study points the other way from the traditional pairing: in a human intestinal Caco-2 cell model, radish seed increased the efflux of six ginsenosides from ginseng, particularly at higher concentrations, which the authors read as inhibiting their absorption.

What has not been tested: radish seed in people with dyspepsia or constipation, raw against stir-baked seed, or the ginseng pairing in any person.

StudyDoseWhat it found
Comprehensive review of Raphani Semen: traditional uses, phytochemistry, pharmacology PMID 35580770Not applicableTraditional use for food retention, abdominal distension, constipation and diarrhea; laboratory activities listed; authors call for study of the material basis
Mouse study: 30 mice on high-fat, high-protein diet; Bao He pill decoction (includes 3 g radish seed) PMID 372283796.63 g per kg a day for 3 daysRestored intestinal mucosal microbial and lactase activity versus the untreated model (P below 0.01)
Caco-2 cell study of radish seed on ginsenoside absorption PMID 38869200Laboratory concentrationsIncreased efflux of six ginsenosides, particularly at higher concentrations; read as inhibited absorption

Doses used in trials and traditional preparations

No human trial gives a radish seed dose for the gut. In the Bao He pill decoction tabulated in the mouse paper the prescription is 18 g of hawthorn, 6 g of medicated leaven, 9 g each of pinellia and poria and 3 g each of tangerine peel, radish seed and forsythia, so radish seed is 3 g of 51 g. The Pharmacopoeia pill lists 50 g of stir-baked radish seed in a batch with 300 g of charred hawthorn. In the tradition the seed is stir-baked and decocted with other herbs or made into pills. We found no single-herb gram dose that we could tie to a primary source.

Treat these figures as a record of what was studied. Whether any amount of radish seed (lai fu zi) suits a particular person is a question for a clinician or pharmacist who knows their history.

Safety

We found no clinical safety data for radish seed in the sources read, including nothing on pregnancy, breastfeeding or children, and the review does not report adverse events in people. Most radish seed is sold inside patent medicines, and a published review of Chinese proprietary medicines in Singapore tabulated reports of excess toxic heavy metals and undeclared drugs in some such products between 1990 and 1997, and a New York laboratory screen of 90 Chinese herbal and patent medicines found Western drugs in 5 samples, 2 of them undeclared or mislabeled; those findings concern the products tested and not every product containing radish seed.

Drug interactions

The one interaction signal is laboratory work with ginseng. In a Caco-2 intestinal cell model radish seed increased the efflux of six ginsenosides (Rg1, Re, Rb1, Rb2, Rc and Rd), which the authors read as inhibition of their absorption and as a mechanism for the antagonism the tradition describes between the two herbs. No human study has measured it. We found no documented interaction with medicines in the sources read.

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Related herbs

TCM Massa fermentata (shen qu) Massa Medicata Fermentata (a fermented mixture, not a single plant) TCM Barley sprout (mai ya) Hordeum vulgare TCM Ginseng Panax ginseng TCM / Western Orange peel Citrus reticulata (chen pi); Citrus sinensis (sweet orange); Citrus aurantium (bitter orange) TCM Pinellia Pinellia ternata

The questions that come up

Is radish seed the same as radish sprouts?

No. Lai fu zi is the ripe seed of Raphanus sativus, a separate part from the sprout or the root eaten as a vegetable. The trials and reviews cited here concern the seed.

Has radish seed been tested in people?

We found no human gut trial of it alone or of Bao He Wan with results. The evidence is a review of traditional uses, a mouse study of a Bao He pill decoction and cell studies.

What does TCM say about it?

TCM classes it as pungent, sweet and neutral, entering the spleen, stomach and lung channels, and uses it to reduce what the texts call food accumulation and to direct qi downward. That is the tradition’s framework.

Why do the texts say it should not be combined with ginseng?

The tradition holds that radish seed opposes ginseng. A Caco-2 cell study found radish seed increased the efflux of six ginsenosides, which the authors read as reduced absorption. It has not been tested in people.

Sources