🌺Thai Traditional Medicine

Guava Leaf (Farang)

Psidium guajava

About Guava Leaf (Farang)

Guava Leaf (Farang) (Psidium guajava) is a herb used in the Thai Traditional Medicine tradition to help with Diarrhea, Diabetes, Immune Support, and Gut Health. The leaves are the part traditionally used, taken internally.

Botanical background

Psidium guajava, the common guava, yellow guava, or lemon guava (known as goiaba in Portuguese and guayaba in Spanish) is an evergreen shrub or small tree native to the Caribbean, Central America and South America. It is easily pollinated by insects; in culture, mainly by the common honey bee, Apis mellifera.

Source: Wikipedia, via iNaturalist

Parts used

Leaves · internal
🍵

Tea / Infusion

1–3 cups daily
  • Steep 1–2 tsp of dried Guava Leaf (Farang) 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 Guava Leaf (Farang) 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 Guava Leaf (Farang) 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 Guava Leaf (Farang) in our references — the guidance below is based on its general effect category, not research on Guava Leaf (Farang) itself. Always confirm with a midwife, doctor, or pediatrician.

Pregnancy

Use Caution

This herb may affect blood sugar levels. Given the importance of stable glucose control in pregnancy, herbs in this category are generally used only under medical guidance, particularly alongside any gestational diabetes monitoring — this is a general, mechanism-based caution, not herb-specific research.

Breastfeeding

Use Caution

Generally used cautiously during breastfeeding, particularly if managing blood sugar medically.

Children

Use Caution

Children are more sensitive to blood-sugar swings given their smaller body size — these herbs are generally used cautiously and under guidance.

Contraindications

  • Autoimmune conditions (lupus, MS, RA) — may overstimulate immune response
  • 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.

⚠️ 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 affect immune activity

Watch for: Immunosuppressants (for transplant or autoimmune conditions)

Immune-stimulating herbs can work against immunosuppressive therapy.

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 Guava Leaf (Farang) 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 Guava Leaf (Farang), 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.