❄️Scandinavian Folk Medicine

Tansy (Rejnfan)

Tanacetum vulgare

About Tansy (Rejnfan)

Tansy (Rejnfan) (Tanacetum vulgare) is a herb used in the Scandinavian Folk Medicine tradition to help with Parasites, Digestive Issues, Fever, and Worms, among 1 other condition it addresses. The aerial parts and leaves are the parts traditionally used, taken internally.

Botanical background

Tansy (Tanacetum vulgare) is a perennial, herbaceous flowering plant of the aster family, native to temperate Europe and Asia. It has been introduced to other parts of the world including North America, and in some areas has become invasive. It is also known as common tansy, bitter buttons, cow bitter, or golden buttons.

Source: Wikipedia, via iNaturalist

Parts used

Aerial Parts · internalLeaves · internal
🍵

Tea / Infusion

1–3 cups daily
  • Steep 1–2 tsp of dried Tansy (Rejnfan) in freshly boiled water for 5–10 minutes.
  • Cover while steeping.
  • Strain and drink.
💧

Tincture

20–40 drops in water, 2–3× daily
  • Pack dried Tansy (Rejnfan) into a jar and cover with 40–60% alcohol.
  • Seal and steep for 4–6 weeks, shaking daily.
  • Strain and store in a dark dropper bottle.
💊

Powder / Capsule

500 mg – 1 g, 1–3× daily
  • Grind dried Tansy (Rejnfan) into a fine powder.
  • Fill size 00 capsules or stir into smoothies or honey.

Pregnancy, Breastfeeding & Children

Pregnancy

Avoid

Tansy is contraindicated in pregnancy — it contains thujone and has a well-documented history as an abortifacient; the essential oil is seriously toxic.

Breastfeeding

Avoid

Contraindicated during breastfeeding due to thujone toxicity.

Children

Avoid

Contraindicated in children due to thujone toxicity.

As a member of the Asteraceae (ragweed/daisy) family, this herb carries a real chance of cross-reaction in anyone allergic to ragweed, chrysanthemums, marigolds, or daisies — introduce cautiously if there's a known allergy.

Contraindications

    Warnings

    ⚠️ Allergic Reactions

    Discontinue immediately if you experience rash, itching, swelling, or difficulty breathing.

    ⚠️ Not Medical Advice

    This information is for educational purposes only. Always consult a qualified healthcare provider before using herbal remedies.

    Drug & herb interactions

    May affect hormone levels

    Watch for: Hormone therapies, oral contraceptives, and tamoxifen or similar medications

    Some herbs have mild phytoestrogenic or hormone-modulating activity that can interact with hormonal medications.

    Where to find in nature

    Native region

    Various global regions

    Climate

    Varied

    Habitat

    Cultivated in traditional medicinal gardens, botanical gardens, and herb farms worldwide

    🌿 To see Tansy (Rejnfan) growing, visit botanical gardens, university plant collections, or specialist herb nurseries near you. If foraging in the wild, always work with an expert identifier — never consume a plant you are not 100% certain of.

    Where to buy

    In store

    • Health food stores (Whole Foods, Natural Grocers, Holland & Barrett, GNC)
    • Naturopathic clinics and integrative medicine practices
    • Specialist herbal apothecaries and herbalist practices
    • Farmers markets with herb vendors

    Online

    iHerb

    Wide selection of standardised extracts, capsules, and powders with lab testing

    Mountain Rose Herbs

    Premium bulk dried herbs — certified organic, ethically sourced

    Starwest Botanicals

    Large selection of certified organic bulk herbs and powders

    Herb Pharm

    High-quality liquid extracts and tinctures, rigorous quality standards

    Amazon

    Convenient — verify brand certifications and check third-party testing

    Etsy

    Small-batch artisan herbalists, hand-harvested and wildcrafted herbs

    Quality tips

    When buying Tansy (Rejnfan), look for: certified organic labelling, clearly stated country of origin, third-party lab testing for heavy metals and pesticides, and a batch expiry date. Standardised extracts offer consistent dosing; bulk dried herbs are more economical for regular use. Avoid very cheap, unlabelled products — quality varies enormously.