Ya Ma Zi
StarLinum usitatissimum L.
Traditionally used for
- Cough & breathing
- Colds & fever
- Digestion
- Bowel health
- Urinary & fluids
- Skin
Cautions & contraindications
- Diabetes
- Toxic — professional use only
☯ TCM Properties
Moistens the Intestines and Unblocks the Bowels; Nourishes Blood and dispels Wind; Resolves Toxicity
Traditional Chinese Uses
Ya Ma Zi (flaxseed) is a mild, oily, neutral herb used in Chinese medicine to nourish Liver Blood, moisten the Intestines to relieve constipation, and soothe dry skin conditions. Its rich omega-3 fatty acid content lubricates the digestive tract, addresses Blood deficiency, and is used topically for dry, itching, or inflammatory skin disorders. As a food-grade herb with broad nutritional value, it exemplifies the Chinese tradition of using seed-based foods for their moistening, nourishing, and Blood-supplementing properties.
Western Herbalism Properties
Traditional Uses
Cherokee Drug-class uses recorded by Native American Ethnobotany database include flaxseed preparations employed as a pulmonary aid and cough medicine (mapped to expectorant), and as a urinary aid (mapped to diuretic). A cold remedy use is also documented. Febrifuge use is omitted per editorial convention. (Source: NAEB; Hamel & Chiltoskey 1975)
Relationships
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Botanical Description
Linum usitatissimum (Linaceae), common flax or linseed, is a slender erect annual herb 30-100 cm tall with narrow lanceolate, sessile, glabrous leaves arranged spirally on the stem. The five-petaled flowers are pale blue (occasionally white or pink), 1.5-2.5 cm across, opening in early morning and shedding petals by midday. The fruit is a globose dehiscent capsule containing 10 glossy, flattened, oval brown seeds rich in mucilage and alpha-linolenic acid. Cultivated for at least 5000 years for fiber (linen) and oil, it grows worldwide in temperate regions on well-drained loamy soils. The dried mature seeds are the medicinal Ya Ma Zi of Chinese pharmacopoeia. (Sources: POWO; PFAF; Wikipedia)
Active Constituents
Alpha-linolenic acid
Omega-3 polyunsaturated fatty acidConcentration: roughly half of the fatty acids of the seed oil, the highest proportion of any common oilseed
The principal omega-3 fatty acid of flaxseed. In the FlaxPAD trial, plasma alpha-linolenic acid rose 2- to 50-fold on 30 g milled flaxseed daily and correlated with the fall in both systolic and diastolic blood pressure, making it one of the two constituents credited with the antihypertensive effect.
Secoisolariciresinol diglucoside (SDG)
Lignan glycosideConcentration: the main lignan of the seed, stored not free but as an oligomer ester-linked through hydroxymethylglutaric acid, which must be alkali-hydrolysed to be measured
Converted by colonic bacteria to the mammalian lignans enterodiol and enterolactone, which are weakly oestrogenic and antioxidant. Circulating enterolignan levels rose 2- to 50-fold in the FlaxPAD trial and correlated with the fall in diastolic blood pressure. In meta-analysis, lignan supplements lowered total and LDL cholesterol (-0.28 and -0.16 mmol/L) whereas flaxseed oil did not.
Linustatin
Cyanogenic diglucosideConcentration: the major cyanogenic glucoside of the seed, reported at roughly 200-350 mg per 100 g and making up the majority of the total cyanogenic glucoside load
Hydrolysed in the gut to release hydrogen cyanide. At normal culinary and herbal doses this is not clinically significant, but it sets a ceiling on safe intake of raw seed and is the reason flaxseed is usually taken ground and, ideally, heat-treated. Baking and other processing reduce the cyanogenic glucoside content.
Neolinustatin
Cyanogenic diglucosideConcentration: the second cyanogenic diglucoside of the seed, present at lower levels than linustatin
Quantified alongside linustatin in validated UPLC-HRMS assays of flaxseed. It contributes to the same cyanide-releasing potential and is reduced by the same processing steps.
Seed mucilage (acidic and neutral arabinoxylans)
Soluble polysaccharideThe bulking, water-holding fraction responsible for the classical action of moistening the intestines and freeing the stool, and for the reduction in constipation symptom scores seen in randomised trials. It is also the constituent behind the practical drug-absorption interactions, since it can trap co-ingested oral medication.
Enterodiol and enterolactone
Mammalian lignan (gut microbial metabolite)Not present in the seed itself but produced from SDG by the colonic microbiota; they are the circulating forms responsible for most of the systemic lignan effects. They have measurable antioxidant activity in vitro and weak oestrogen-receptor activity, which is the basis of the theoretical caution in hormone-sensitive disease.
⚠ Drug Interactions
Orally administered drugs generally (notably levothyroxine, warfarin, oral contraceptives, digoxin, lithium)
Flaxseed is a mucilaginous bulk laxative. The soluble arabinoxylan mucilage forms a viscous gel that slows gastric emptying and can physically entrap co-ingested drug, and the accelerated transit that produces the therapeutic effect shortens the window for absorption. This is a general class effect of bulk-forming laxatives rather than a metabolic interaction.
Clinical note: Take other oral medicines at least one hour before or two hours after flaxseed. Always give flaxseed with a full glass of water; taken dry or with too little fluid it can cause oesophageal or intestinal obstruction, particularly in patients with strictures or impaired motility.
Antihypertensive drugs (ACE inhibitors, ARBs, calcium channel blockers, diuretics)
In the FlaxPAD randomised, double-blind, placebo-controlled trial of 110 peripheral artery disease patients, 30 g of milled flaxseed daily for six months lowered systolic blood pressure by about 10 mmHg and diastolic by about 7 mmHg versus placebo, and by 15/7 mmHg in those entering with systolic pressure at or above 140 mmHg. A meta-analysis of 15 trials and 1302 participants confirmed a smaller but significant pooled effect of -2.85 mmHg systolic and -2.39 mmHg diastolic, larger in trials lasting 12 weeks or more. Notably the effect was selective for hypertensive patients.
Clinical note: This is a genuine, dose-relevant antihypertensive effect at 30 g daily, not a nominal one. In a treated hypertensive patient, monitor blood pressure over the first few weeks and be prepared for the prescribing physician to need to reduce antihypertensive doses.
Antidiabetic drugs (insulin, sulfonylureas, metformin)
In a randomised trial in 53 constipated patients with type 2 diabetes, 10 g of flaxseed twice daily for 12 weeks lowered fasting plasma glucose by 26.7 mg/dl and HbA1c by 0.8 percent against placebo, alongside falls in weight, BMI, total cholesterol and LDL. The likely mechanism is the mucilage slowing carbohydrate absorption rather than any effect on insulin secretion.
Clinical note: In insulin- or sulfonylurea-treated diabetics, advise more frequent glucose self-monitoring for the first month and flag to the prescriber that dose reduction may be needed.
Stimulant anthraquinone laxatives (Senna alexandrina, Frangula alnus) in combination products
This is not theoretical: marketed flaxseed laxative preparations exist in which the seed is coated with Senna alexandrina and Frangula alnus extracts, so a patient may be taking anthraquinone stimulants without realising it. Layering the practitioner's own senna or rhubarb prescription on top of such a product doubles the stimulant exposure while the patient believes they are only taking a bulk laxative.
Clinical note: Ask to see the actual product a patient is using rather than accepting the description flaxseed. Plain milled flaxseed and coated flaxseed laxative preparations are not the same drug.
Hei Zhi Ma (Sesamum indicum) and Huo Ma Ren (Cannabis sativa) — name cross-mixing and substitution
Ya Ma Zi (Linum usitatissimum) has historically been called Hu Ma, a name that also attaches to sesame, and the names of Ya Ma Zi, Hei Zhi Ma and Huo Ma Ren have cross-mixed over time. Hong Kong's Chinese medicine regulator lists Semen Lini and Semen Sesami Nigrum among the readily confused materials requiring careful identification. The three drugs are botanically unrelated: only flaxseed carries the lignan and cyanogenic glucoside profile above, only Huo Ma Ren comes from Cannabis, and only sesame is the classical Liver-and-Kidney-supplementing Hei Zhi Ma.
Clinical note: Specify the binomial when ordering. Inspect the material: flaxseed is flat, glossy and pointed at one end, sesame is smaller and matte, and Huo Ma Ren is a rounded grey-brown achene. Never accept Hu Ma as an unqualified order name.
Anticoagulant and antiplatelet drugs (warfarin, aspirin, clopidogrel)
High intakes of alpha-linolenic acid can modestly reduce platelet aggregation, a general omega-3 class effect. No controlled trial or credible case report has demonstrated a clinically significant bleeding interaction between flaxseed and an anticoagulant, and the trials above at 30 g daily for six months reported no bleeding signal.
Clinical note: No routine restriction is warranted. Mention flaxseed use at the next INR check for warfarinised patients, and stop high-dose flaxseed oil supplements before elective surgery as with any omega-3 supplement.
Raw, unheated or immature flaxseed at high intake (cyanogenic glucoside load)
The seed carries linustatin and neolinustatin, cyanogenic diglucosides hydrolysed in the gut to release hydrogen cyanide. Content varies substantially between varieties, and processing methods measurably reduce it. Additive load matters when flaxseed is combined with other cyanogenic drugs such as Ku Xing Ren, Tao Ren or Yu Li Ren, or with cassava in the diet.
Clinical note: Keep to conventional doses, prefer ground and heat-treated seed for regular use, and avoid stacking flaxseed with other cyanogenic kernel drugs in the same prescription. Caution in thiocyanate-related thyroid disease and in iodine deficiency.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 9–15 g | Daily | — | — | 中国药典 2020 【用法与用量】9～15g。 【注意】大便滑泻者禁用。 【性味与归经】甘，平。归肺、肝、大肠经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Strong evidence · 5 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
2
2 verified · 0 unverified
Randomized controlled trial
3
2 verified · 1 unverified
Show 3 studies
- Potent Antihypertensive Action of Dietary Flaxseed in Hypertensive Patients
- A randomized trial of the effects of flaxseed to manage constipation, weight, glycemia, and lipids in constipated patients with type 2 diabetes
- Effect of flaxseed or psyllium vs. placebo on management of constipation, weight, glycemia, and lipids: A randomized trial in constipated patients with type 2 diabetes
Other clinical trial
0
Observational / case report
0
In vitro / animal
0
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Potent Antihypertensive Action of Dietary Flaxseed in Hypertensive Patients
In a prospective, double-blinded, placebo-controlled randomised trial, 110 patients with peripheral artery disease ate foods containing 30 g of milled flaxseed or placebo daily for six months. Plasma alpha-linolenic acid and enterolignans rose 2- to 50-fold in the flaxseed group only, with no difference in body weight. Systolic pressure was about 10 mmHg lower and diastolic about 7 mmHg lower than placebo at six months, and patients entering with systolic pressure at or above 140 mmHg gained 15 mmHg systolic and 7 mmHg diastolic. The effect was selective for hypertensive patients, and the authors describe it as among the most potent antihypertensive effects achieved by a dietary intervention.
Meta-analysis of the effects of flaxseed interventions on blood lipids
Twenty-eight randomised controlled trials were pooled. Flaxseed interventions reduced total cholesterol by 0.10 mmol/L and LDL cholesterol by 0.08 mmol/L overall, with significant reductions for whole flaxseed (-0.21 and -0.16 mmol/L) and lignan supplements (-0.28 and -0.16 mmol/L) but not for flaxseed oil. Effects were larger in women, especially postmenopausal women, and in those with high baseline cholesterol. HDL cholesterol and triglycerides were unchanged. The lignan-versus-oil split is clinically important, since it means the whole seed and the pressed oil are not interchangeable for this indication.
Effects of flaxseed supplements on blood pressure: A systematic review and meta-analysis of controlled clinical trial
Fifteen trials with 19 treatment arms and 1302 participants were pooled. Flaxseed supplementation lowered systolic blood pressure by 2.85 mmHg and diastolic by 2.39 mmHg. The effect on both was greater in trials of 12 weeks or longer than in shorter ones. Systolic reduction was significant with flaxseed powder but not with oil or lignan extract, while diastolic reduction reached significance with both powder and oil but not lignan extract, again showing that the preparation used determines the effect.
A randomized trial of the effects of flaxseed to manage constipation, weight, glycemia, and lipids in constipated patients with type 2 diabetes
In a single-blinded randomised controlled trial, 53 constipated patients with type 2 diabetes received 10 g of flaxseed pre-mixed in cookies twice daily or placebo cookies for 12 weeks, with constipation assessed by ROME III stool diary. Constipation symptom scores fell 2.46 versus 0.41 for placebo, with weight down 3.8 kg, fasting plasma glucose down 26.7 mg/dl, HbA1c down 0.8 percent, total cholesterol down 37.3 mg/dl and LDL down 21.0 mg/dl, all significant against placebo. Compliance was good and no adverse effects were observed.
Effect of flaxseed or psyllium vs. placebo on management of constipation, weight, glycemia, and lipids: A randomized trial in constipated patients with type 2 diabetes
A randomised trial in constipated patients with type 2 diabetes comparing flaxseed with psyllium and with placebo on constipation symptoms, weight, glycaemic control and lipids. It is the head-to-head companion to the same group's placebo-controlled flaxseed trial and supports flaxseed as at least comparable to a conventional bulk-forming laxative in this population, with additional metabolic benefit.
⚠ Safety & Contraindications
- Diabetes
- Toxic — professional use only
Contraindications
Its use is prohibited in patients with diarrhea.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, p. 95.
Historical Texts
Ben Cao Tu Jing
Northern Song dynasty, 1061Ben Cao Gang Mu
Ming dynasty, 1596References
- Zhao M, Bergaentzle M, Flieller A, Marchioni E. Development and validation of an ultra-high performance liquid chromatography-high resolution mass spectrometry method for simultaneous quantification of cyanogenic glycosides and secoisolariciresinol diglucoside in flaxseed (Linum usitatissimum L.) . Journal of Chromatography A (2019) [DOI]
- Wang YL, Liu ZJ, Liu Q, Ma JN, Hattori M, Ma CM. Simultaneous Quantification of Secoisolariciresinol Diglucoside and Cyanogenic Glycosides in Flaxseed Products by Various Processing Methods . Food Analytical Methods (2013) [DOI]
- Shim YY, Olivia CM, Liu J, Boonen R, Shen J, Reaney MJT. Secoisolariciresinol Diglucoside and Cyanogenic Glycosides in Gluten-free Bread Fortified with Flaxseed Meal . Journal of Agricultural and Food Chemistry (2016) [DOI]
- Kitts DD, Yuan YV, Wijewickreme AN, Thompson LU. Antioxidant activity of the flaxseed lignan secoisolariciresinol diglycoside and its mammalian lignan metabolites enterodiol and enterolactone . Molecular and Cellular Biochemistry (1999) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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