🌺Thai Traditional Medicine

Cassia Fistula (Khun)

Cassia fistula

About Cassia Fistula (Khun)

Cassia Fistula (Khun) (Cassia fistula) is a herb used in the Thai Traditional Medicine tradition to help with Constipation, Liver Support, Fever, and Skin Health. The aerial parts and leaves are the parts traditionally used, used both internally and topically.

Botanical background

Cassia fistula, known as the golden rain tree, canafistula and by other names, is a flowering plant in the family Fabaceae. The species is native to the Indian subcontinent and adjacent regions of Southeast Asia. It ranges from southern Pakistan eastward throughout India to Myanmar and Thailand and south to Sri Lanka. It is the state flower of Kerala in India and of immense importance amongst the Malayali population. It is a popular ornamental plant and...

Source: Wikipedia, via iNaturalist

Parts used

Aerial Parts · bothLeaves · both
🍵

Tea / Infusion

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

Topical / Poultice

1–2× daily as needed
  • Mash fresh Cassia Fistula (Khun) or mix the powder with a little water to form a paste.
  • Apply to the affected area for 20–30 minutes.
🫙

Infused Oil

Massage into affected area 1–2× daily
  • Fill a jar with dried Cassia Fistula (Khun).
  • Pour over a carrier oil until submerged.
  • Leave for 4–6 weeks, then strain.
  • Use topically or as a salve base.
🛁

Herbal Bath

2–3× per week as needed
  • Brew 4–6 tbsp of Cassia Fistula (Khun) in 1 litre of hot water for 15 minutes, strain, and add to a warm bath.
  • Soak for 20–30 minutes.

Pregnancy, Breastfeeding & Children

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

Pregnancy

Use Caution

This herb is processed through the liver, which is already working harder during pregnancy — generally used cautiously and not at high/concentrated doses without guidance. This is a general, mechanism-based caution, not herb-specific research.

Breastfeeding

Use Caution

Liver-processed compounds can appear in breast milk — generally used cautiously and in moderation.

Children

Use Caution

A child's liver is still developing its full drug/herb-processing capacity — these herbs are generally used cautiously and at reduced, age-appropriate doses.

Contraindications

  • Active liver disease — monitor liver enzymes with long-term use

Warnings

⚠️ Liver Health

Some herbs used for liver conditions can be hepatotoxic at high doses. Have liver function monitored if using long-term.

⚠️ 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.

Processed by the liver

Watch for: Any medication that is also processed by liver enzymes (ask your pharmacist — this includes many common prescriptions)

Can alter how quickly the body clears certain medications, raising or lowering their effective dose.

Where to find in nature

Native region

Thailand, Myanmar, Laos, Cambodia

Climate

Tropical monsoon

Habitat

Tropical forests, temple gardens, and village herb plots of Southeast Asia

🌿 To see Cassia Fistula (Khun) 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

  • Thai and Southeast Asian grocery stores
  • Asian supermarkets with herbal and fresh produce sections
  • Health food stores (Whole Foods, Natural Grocers, Holland & Barrett, GNC)
  • Naturopathic clinics and integrative medicine practices
  • Specialist herbal apothecaries and herbalist practices

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 Fistula (Khun), 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.