flax seed


Complementary/Alternative Medicine: This monograph describes a natural or herbal product that is not subject to FDA guidelines for medicines. Patients and clinicians are advised to read package labels carefully to ensure safe and efficacious use.

flaks seed

Trade Name(s)

  • Linum usitatissimum
  • linseed
  • phytoestrogen

Ther. Class.


lipid-lowering agents

Common Uses

  • Constipation.
  • Hypercholesterolemia.
  • Menopausal symptoms.
  • Systemic lupus erythematosus (SLE) nephritis.


Flaxseed contains alpha-linolenic acid which lowers serum cholesterol and reduces platelet aggregation. Ten grams of flaxseed contains 4 grams of dietary fiber which also helps lower cholesterol and increases fecal elimination of bile acids. Flaxseed is an indirect food source of lignans which alter estrogen metabolism to produce less active estrogen metabolites. Flaxseed improves renal function by decreasing blood viscosity, reducing serum cholesterol and reducing inflammatory response.

Therapeutic Effect(s):

  • Reduced serum cholesterol.
  • Improved renal function.
  • Increased bowel movements.


Absorption: Unknown

Distribution: Unknown

Metabolism and Excretion: Unknown

Half-life: Unknown




Contraindicated in:

  • Hypersensitivity;
  • Gastrointestinal obstruction.

Use Cautiously in:

  • Pregnancy and lactation;
  • Bleeding disorders;
  • Diabetes;
  • Hormone sensitive cancers/conditions.

Adverse Reactions/Side Effects

Endo: hypoglycemia

GI: bloating, diarrhea, flatulence, nausea

Hemat: increased bleeding time

Misc: allergic reactions

* CAPITALS indicate life-threatening.
Underline indicate most frequent.


Natural Drug Interaction


Increased risk of bleeding with herbs that have anticoagulant/antiplatelet properties including  clove garlic ginger gingko ginseng  and others.


Note: Flaxseed oil contains the alpha-linolenic acid component of flaxseed, not the fiber or lignan components. It may share the purported lipid-lowering properties of flaxseed but not the proposed laxative or anti-estrogenic properties.

PO (Adults): Hypercholesterolemia: 40–50 grams/day.  SLE nephritis: 15 grams twice daily.  Mild menopausal symptoms: 40 grams/day.


Whole or ground seeds


  • Assess for abdominal distention, presence of bowel sounds, and usual pattern of bowel function.
  • Assess color, consistency, and amount of stool produced.

Lab Test Considerations:

Monitor serum glucose, triglycerides, alkaline phosphatase, lipid panel, RBC count, coagulation panel, inflammatory markers, hormone panel, and prostate specific antigen (PSA) before and periodically during therapy.


  • PO Administer with food or mix in food.

Patient/Family Teaching

  • Instruct patient to follow directions provided with product.
  • Encourage patients to use other forms of bowel regulation, such as increasing bulk in the diet, increasing fluid intake (6–8 full glasses/day), and increasing mobility. Normal bowel habits are variable and may vary from 3 times/day to 3 times/wk.
  • Advise patient that this medication should be used in conjunction with diet restrictions (fat, cholesterol, carbohydrates, alcohol), exercise, and cessation of smoking.
  • Advise patient not to use laxatives when abdominal pain, nausea, vomiting, or fever is present.
  • Instruct female patients to notify health care professional promptly if pregnancy is planned or suspected.

Evaluation/Desired Outcomes

  • A soft, formed bowel movement.
  • Decrease in serum cholesterol levels.