⛩️Kampo / Japanese Medicine

Cinnamon (Keihi)

Cinnamomum cassia

About Cinnamon (Keihi)

Cinnamon (Keihi) (Cinnamomum cassia) is a herb used in the Kampo / Japanese Medicine tradition to help with Circulation, Pain, Diabetes, and Cold Extremities. The bark is the part traditionally used, taken internally.

Botanical background

Cinnamomum cassia, called Chinese cassia or Chinese cinnamon, is an evergreen tree originating in southern China and widely cultivated there and elsewhere in South and Southeast Asia. It is one of several species of Cinnamomum used primarily for its aromatic bark, which is used as a spice. The buds are also used as a spice, especially in India, and were used by the ancient Romans.

Source: Wikipedia, via iNaturalist

Parts used

Bark · internal
🍵

Tea / Infusion

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

Pregnancy, Breastfeeding & Children

Pregnancy

Use Caution

Culinary seasoning amounts (especially true Ceylon cinnamon) are considered safe; medicinal/concentrated doses of Cassia cinnamon are best limited due to coumarin content, which in large amounts may affect the liver and has a mild blood-thinning reputation.

Breastfeeding

Likely Safe

Normal culinary use is considered compatible with breastfeeding.

Children

Likely Safe

Culinary amounts are fine for children; avoid concentrated supplements and be aware Cassia cinnamon's coumarin content adds up with regular heavy use.

Contraindications

  • Pre-surgery — discontinue at least 2 weeks prior (potential antiplatelet effect)
  • Diabetes medications — may enhance hypoglycaemic effect; monitor blood glucose closely

Warnings

Diabetes Medications

May enhance the blood sugar–lowering effect of insulin or oral diabetes medications. Monitor blood glucose closely.

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

Diabetes medications

Cassia cinnamon may lower blood sugar; monitor glucose closely with regular high-dose use.

Liver-metabolized medications

High-dose cassia cinnamon contains coumarin, a liver-stressing compound.

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 Cinnamon (Keihi) 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 Cinnamon (Keihi), 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.