⛩️Kampo / Japanese Medicine

Cassia Seed (Ketsumeishi)

Senna obtusifolia

About Cassia Seed (Ketsumeishi)

Cassia Seed (Ketsumeishi) (Senna obtusifolia) is a herb used in the Kampo / Japanese Medicine tradition to help with Eye Health, Constipation, High Blood Pressure, and Cholesterol. The seeds are the part traditionally used, taken internally.

Botanical background

Senna obtusifolia (Chinese senna, American sicklepod or sicklepod) is a legume in the genus Senna, sometimes separated in the monotypic genus Diallobus. It grows wild in North, Central, and South America, Asia, Africa, and Oceania, and is considered a particularly serious weed in many places. It has a long-standing history of confusion with Senna tora and that taxon in many sources actually refers to the present species.

Source: Wikipedia, via iNaturalist

Parts used

Seeds · internal
🫖

Decoction

1–2 cups daily
  • Add 1–2 tsp of dried Cassia Seed (Ketsumeishi) to 2 cups of cold water.
  • Bring to a boil, then simmer for 15–20 minutes.
  • Strain and drink warm.
💧

Tincture

20–40 drops in water, 2–3× daily
  • Pack dried Cassia Seed (Ketsumeishi) 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 Cassia Seed (Ketsumeishi) into a fine powder.
  • Fill size 00 capsules or stir into smoothies or honey.

Pregnancy, Breastfeeding & Children

No herb-specific pregnancy/child safety research is documented for Cassia Seed (Ketsumeishi) in our references — the guidance below is based on its general effect category, not research on Cassia Seed (Ketsumeishi) itself. Always confirm with a midwife, doctor, or pediatrician.

Pregnancy

Use Caution

This herb may affect blood pressure. Since blood pressure changes are a significant pregnancy risk factor (e.g. preeclampsia), herbs in this category are generally used only under medical supervision rather than self-directed — this is a general, mechanism-based caution, not herb-specific research.

Breastfeeding

Use Caution

Generally used cautiously during breastfeeding, particularly if the nursing parent is also on blood pressure medication.

Children

Use Caution

Blood-pressure-active herbs are generally used cautiously in children and typically only under pediatric guidance.

Contraindications

  • Pre-surgery — discontinue at least 2 weeks prior (potential antiplatelet effect)

Warnings

⛔ 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 drug absorption

Watch for: Any oral medication taken around the same time

High-fiber or mucilage-rich herbs can slow or reduce how much of another oral drug is absorbed — space doses a couple of hours apart.

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.

May thin the blood

Watch for: Anticoagulants (warfarin), antiplatelets (aspirin, clopidogrel), and other blood-thinning herbs or supplements (ginkgo, garlic, fish oil, vitamin E)

Combining blood-thinning substances can increase bleeding risk, including before surgery or dental work.

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 Cassia Seed (Ketsumeishi) 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 Cassia Seed (Ketsumeishi), 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.