⛩️Kampo / Japanese Medicine

Prunella (Kago So)

Prunella vulgaris

About Prunella (Kago So)

Prunella (Kago So) (Prunella vulgaris) is a herb used in the Kampo / Japanese Medicine tradition to help with High Blood Pressure, Thyroid, Eye Health, and Inflammation. The aerial parts and leaves are the parts traditionally used, taken internally.

Botanical background

Prunella vulgaris (known as common self-heal , heal-all, woundwort, heart-of-the-earth, carpenter's herb, brownwort and blue curls) is an herbaceous plant in the genus Prunella.

Source: Wikipedia, via iNaturalist

Parts used

Aerial Parts · internalLeaves · internal
🍵

Tea / Infusion

1–3 cups daily
  • Steep 1–2 tsp of dried Prunella (Kago So) 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 Prunella (Kago So) 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 Prunella (Kago So) into a fine powder.
  • Fill size 00 capsules or stir into smoothies or honey.

Contraindications

  • Pregnancy & breastfeeding — insufficient safety data; consult your doctor
  • Children under 12 — therapeutic dosage not established
  • Pre-surgery — discontinue at least 2 weeks prior (potential antiplatelet effect)
  • Thyroid disorders — may interfere with levothyroxine and other thyroid medications

Warnings

⚠️ Pregnancy & Breastfeeding

Safety during pregnancy and breastfeeding has not been established for most herbal remedies. Consult your midwife or doctor before use.

⛔ Heart & Blood Pressure Medications

May interact with antihypertensive drugs, blood thinners, or cardiac medications. Do not combine without medical guidance.

⚠️ 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 blood pressure

Watch for: Antihypertensive medications (ACE inhibitors, beta-blockers, calcium channel blockers, diuretics)

Combined use can push blood pressure too high or too low — monitor readings if you take blood pressure medication.

Where to find in nature

Native region

Japan, China, Korea

Climate

Temperate to subtropical

Habitat

Mountain forests and cultivated herb farms across Japan and East Asia

🌿 To see Prunella (Kago So) 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 Prunella (Kago So), 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.