⛩️Kampo / Japanese Medicine

Dioscorea (Yamaimo)

Dioscorea opposita

About Dioscorea (Yamaimo)

Dioscorea (Yamaimo) (Dioscorea opposita) is a herb used in the Kampo / Japanese Medicine tradition to help with Digestive Issues, Diabetes, Fatigue, and Kidney Support. The aerial parts and leaves are the parts traditionally used, taken internally.

Botanical background

Dioscorea oppositifolia is a type of yam (Dioscorea) native to Myanmar (Burma) and to the Indian Subcontinent (India, Sri Lanka, Bangladesh).

Source: Wikipedia, via iNaturalist

Parts used

Aerial Parts · internalLeaves · internal
🍵

Tea / Infusion

1–3 cups daily
  • Steep 1–2 tsp of dried Dioscorea (Yamaimo) 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 Dioscorea (Yamaimo) 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 Dioscorea (Yamaimo) 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
  • Significant kidney impairment — diuretic herbs may worsen renal function
  • Diabetes medications — may enhance hypoglycaemic effect; monitor blood glucose closely

Warnings

⚠️ Pregnancy & Breastfeeding

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

⛔ Diabetes Medications

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

⚠️ Kidney Disease

Some diuretic herbs are contraindicated in those with kidney disease. Consult your doctor if you have impaired kidney function.

⚠️ 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 sugar

Watch for: Insulin and oral diabetes medications (metformin, sulfonylureas)

Additive blood-sugar-lowering effects can risk hypoglycemia — monitor glucose closely.

May have a stimulant effect

Watch for: Other caffeine-containing products, MAOIs, and stimulant medications (for ADHD or weight loss)

Additive stimulant effects can raise heart rate and blood pressure.

May have a diuretic effect

Watch for: Diuretic medications and lithium

Additive fluid loss can affect electrolyte balance and change how the body clears lithium.

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 Dioscorea (Yamaimo) 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 Dioscorea (Yamaimo), 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.