Flaxseed (Linum usitatissimum)
Photo: Quartl · CC BY-SA 3.0
- Digestive
- 2 conditions
- Licensed photo
Overview
Flaxseed (Linum usitatissimum), also called linseed, is a slender annual plant growing up to about 3 ft (1 m). It produces narrow leaves, delicate blue flowers, and spherical seed capsules containing shiny, flat seeds. Long cultivated in the Middle East and beyond, flaxseeds are rich in fatty acids (particularly alpha-linolenic acid), protein, fiber, mucilage, and lignans (phytoestrogens). Flaxseed and flaxseed oil supplements are promoted for the heart, brain and immune system, although NCCIH describes the research on them as being of varying quality.
Traditional uses & properties
Bulk Laxative (traditional use): Traditionally used for constipation; MSK says clinical studies found flaxseed improved constipation symptoms. Phytoestrogenic: Lignans are plant estrogens, and MSK says they may help mild menopausal symptoms like hot flashes. Omega-3-Rich: High in alpha-linolenic acid, a plant omega-3 fatty acid.
Safety & precautions
Oxidation: Ground flaxseeds spoil quickly due to oxidation. Grinding fresh seeds as needed is best. Immature Seeds: Avoid consuming unripe seeds - they may be toxic. Storage: Ground or cracked seeds should be kept in an airtight container in the fridge.
Educational reference only - not medical advice. Herbs can interact with medications. Consult a qualified healthcare provider before use. Full disclaimer.
Drug interactions
Interaction data is not available for this herb - talk to a pharmacist before combining it with any medication. A blank entry here means we have not documented interactions, not that none exist.
Habitat
Originally from temperate regions in Europe and Asia, flax is now widely cultivated globally, including in Canada, the U.S., Argentina, and northern Europe. Sown in spring, it is harvested in late summer or early fall once seeds have ripened.
Sources
The interaction notes and the statements on this page that name a source were written by HerbMate from these references, which were last checked in October 2026. They are summaries, not medical advice; ask a pharmacist about your own medicines.
Traditionally used for
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Frequently asked questions
What is Flaxseed (Linum usitatissimum) traditionally used for?
Traditional sources describe Flaxseed (Linum usitatissimum) as follows: Bulk Laxative (traditional use): Traditionally used for constipation; MSK says clinical studies found flaxseed improved constipation symptoms. Phytoestrogenic: Lignans are plant estrogens, and MSK says they may help mild menopausal symptoms like hot flashes. Omega-3-Rich: High in alpha-linolenic acid, a plant omega-3 fatty acid.
What safety cautions apply to Flaxseed (Linum usitatissimum)?
Oxidation: Ground flaxseeds spoil quickly due to oxidation. Grinding fresh seeds as needed is best. Immature Seeds: Avoid consuming unripe seeds - they may be toxic. Storage: Ground or cracked seeds should be kept in an airtight container in the fridge.
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