This large genus of some 200 species of annuals, biennials, perennials, and shrubs, is found in northern temperate regions. Some are grown as ornamentals for their numerous, brightly colored flowers, which are produced throughout the summer. Linum usitatissimum is one of the world's oldest crop plants, known in cultivation as a source of flax since 5000 BCE. In the 8th century, the Emperor Charlemagne decreed that flax seeds should be consumed in order to maintain good health. Though classified as a species, L. usitatissimum is probably an ancient cultigen, derived from L. bienne; it is not known in the wild. There are two distinct strains of L. usitatissimum; the taller flax, with fewer branches and flowers, which yields fiber; and the shorter, more floriferous and fruitful linseed, which is grown for oil and as a fodder crop. Seeds contain 30-40 percent of a fixed oil, known as linseed oil, which consists of mainly linoleic and linolenic acids. In common with many members of the Linaceae, Rosaceae, and Caprifoliaceae families, they also contain cyanogenic glycosides, or prussic acid. In small amounts, these compounds stimulate respiration and improve digestion but, in excess, cause respiratory failure and death. There is no indication that recommended doses of L. usitatissimum pose any threat. The related L. carhaticum (Mountain or purging flax) was once used as a laxative and anti-rheumatic.

One of the earliest cultivated plants, flax was valued by ancient Egyptians and Greeks for the fibers taken from its stem, which were woven into cloth (known as linen). Studies have shown the flaxseed oil, a rich source of omega-3 fatty acids, may help lower total cholesterol and blood fat levels, fight inflammation, decrease artherosclerosis, inhibit clot formation, and increase HDL "good" cholesterol levels.

Erect annual with narrow, gray-green leaves, to 2.5cm (1in) long. Sky-blue, saucer shaped flowers, 3cm (1¼in) across, appear in summer, followed by spherical capsules, about 1cm (3/8in) in diameter, containing shiny, oval, flattened seeds.

Common Name:
Other Names:
Flaxseed, Linseed, Lint Bells, Linum, Winterlien
Botanical Name:
Linum usitatissimum
Well-drained to dry sandy soil in sun. Dislikes being transplanted.
By seed sown in situ in spring.
Plants are cut when mature for fiber extraction. Seeds are collected when ripe, stored whole, or pressed for oil.
80cm-1.2m (2½-4ft)
30cm-60cm (12-24in)
Parts Used:
Whole Plant, stems, seeds, oil extracted from plant or seed.
A sweet, mucilaginous herb that is laxative and expectorant, soothes irritated tissues, controls coughing, and relieves pain.
Medicinal Uses:
Internally as a bulk laxative for chronic constipation and diverticulitis (crushed seeds mixed with breakfast cereals and ample liquids), gastritis, pharyngitis (macerated seeds), chronic bronchial complaints, coughs, and sore throat; as a dietary supplement for eczema, menstrual problems, hardening of the arteries, and rheumatoid arthritis (oil). Externally for bronchitis, pleurisy, sore throat, burns, scalds, boils, abscesses, and ulcers. Crushed seeds are combined, as a poultice, with Sinapsis alba (see, White Mustard) for chest complaints, and with honey and lemon as a cough remedy.
To treat constipation, diverticulitis, irritable bowel syndrome, lupus-related kidney inflammation, high cholesterol, and skin inflammation. Germany's Commission E has approved the use of flax to treat constipation and inflammation of the skin. Flaxseed oil is a rich source of omega-3 fatty acids may be at lower risk of developing Alzheimer's disease. Omega-3's may also decrease the formation of plaque in the coronary arteries.
Typical Dose:
A daily internal dose of flax may range from 35 to 50 mg of crushed seeds or 1000 to 3000 mg of flaxseed oil. For external use, 30 to 50 gm of flaxseed flour might be combined with a small amount of water, heated, cooled until its warm to the touch, then applied to a wound to stimulate healing.
Possible Side Effects:
Flax's side effects include diarrhea and intestinal obstruction, in taken with insufficient amounts of water.
Drug Interactions:
Taking flax with these drugs may increase the risk of hypoglycemia (low blood sugar):
Acarbose, (Prandase, Precose)
Acetohexamide, (Acetohexamide)
Chlorpropamide, (Diabinese, Novo-Propamide)
Gliclazide, (Diamicron, Gliclazide)
Glimepiride, (Amaryl)
Glipizide, (Glucotrol)
Glipizide and Metformin, (Metaglip)
Gliquidone, (Beglynor, Glurenorm)
Glyburide, (Diabeta, Micronase)
Glyburide and Metformin, (Glucovance)
Insulin, (Humulin, Novolin R)
Metformin, (Glucophage, Riomet)
Miglitol, (Glyset)
Nateglinide, (Starlix)
Pioglitazone, (Actos)
Repaglinide, (GlucoNorm, Prandin)
Rosiglitazone, (Avandia)
Rosiglitazone and Metformin, (Avandamet)
Tolazamide, (Tolinase)
Tolbutamide, (Apo-Tolbutamide, Tol-Tab)
Taking flaxseed with these drugs may reduce or prevent drug absorption:
All drugs taken orally, (All Oral Medications)
Digitalis, (Digitek, Lanoxin)
Lab Test Alterations (by flaxseed):
  • May decrease total cholesterol and LDL "bad" cholesterol.
  • May decrease blood glucose.
  • May increase triglyceride levels (when partially deffated flaxseed is used).
Lab Test Alterations (by flaxseed oil):
  • May increase prothrombin time (PT) test results.
  • May decrease triglyceride levels in those with hyperlipoproteinemia.
Disease Effects:
  • May worsen bleeding disorders by interfering with platelet aggregation.
  • May worsen diabetes by pushing blood sugar levels too low.
  • This herb may have estrogen-like effects and should not be used by women with estrogen-sensitive breast cancer or other hormone-sensitive conditions.
  • May worsen cases of intestinal inflammation.
Culinary Uses:
Seeds are added to breads, sprouted for salads, infused as a tea, or roasted as a coffee substitute.
Economic Uses:
Seeds are important as a source of linolenic acid (omega-3 oil) in food supplements; also as an egg substitute in baked products for special diets. Fibers yield flax, used to make linen. Linseed oil is used in the manufacture of paints and floorings; seed residue is made into linseed cake for animal feed.
Encyclopedia of Herbs by Deni Brown Copyright © 1995, 2001 Dorling Kindersley Limited Pg 263
The Essential Herb-Drug-Vitamin Interaction Guide by Geo. T. Grossberg,MD and Barry Fox,PhD Copyright©2007 Barry Fox,PhD. Pp.222-223