Liu Yi San (六一散) — Six-to-One Powder

Liu Yi San is a classical Chinese herbal formula used primarily for mild heatstroke or summer heat illness. It is prescribed for summer Heat with Damp affecting the lower burner:

On this page

1. Overview
2. TCM pattern
3. Key herbs
4. Formula actions
5. Conditions treated
6. Cautions
7. Frequently asked questions

Overview

Liu Yi San — the “Six-to-One Powder” — is from Liu Wansu’s Jin-dynasty Shang Han Biao Ben. The name describes the proportion: six parts Hua Shi (talc) to one part Gan Cao. It is the simplest classical answer to summer Heat with Damp — Hua Shi drains Damp-Heat downward through urination while Gan Cao protects fluids. The formula is widely used as a base remedy for heatstroke, summer thirst, scant dark urine and acute Damp-Heat in the lower burner (cystitis, urinary tract infection).

I prescribe Liu Yi San as part of bespoke herbal formulas from pharmaceutical-grade granules sourced from Sun Ten in Taiwan.

TCM pattern

Liu Yi San is prescribed for summer Heat with Damp affecting the lower burner:

• Fever, restlessness, irritability in hot weather
• Thirst, dry mouth, sweating
• Scant dark yellow urine
• Urinary frequency, urgency, burning
• Possibly diarrhoea with Damp-Heat
• Tongue — red, yellow coat
• Pulse — slippery, rapid

Key herbs

1. Hua Shi (talc, 18-30g) — chief; clears summer Heat and drains Damp through urination
2. Gan Cao (Rx. Glycyrrhizae, 3-5g) — clears Heat; resolves toxin; protects fluids; harmonises

Formula actions

1. Clears summer Heat
2. Resolves Damp through urination
3. Generates fluids and quenches thirst

Conditions treated

1. Mild heatstroke or summer Heat illness
2. Acute uncomplicated cystitis with Damp-Heat pattern
3. Summer dehydration with scant dark urine
4. Mild summer diarrhoea with Damp-Heat
5. Heat rash or prickly heat in hot weather
6. As a base formula with other ingredients added for stronger summer Heat clearance (Bi Yu San, Yi Yuan San)

Cautions

Severe heatstroke (core temperature above 40°C, confusion, collapse) is a medical emergency — call 999, do not rely on herbs.

Acute pyelonephritis (fever, loin pain, vomiting^[12]) requires urgent antibiotics — herbs are supportive only.

Hua Shi should be wrapped during traditional decoction; granule form bypasses this issue.

Not appropriate for Yang-deficient cold patterns or pure Yin-deficient thirst without summer Heat.

Always consult a qualified Chinese herbalist registered with the RCHM.

Prefer to be treated from home? Chinese herbal medicine online consultations are available throughout the UK and worldwide.

Frequently asked questions about Liu Yi San

What is Liu Yi San used for?

Liu Yi San is used for mild heatstroke or summer heat illness, acute uncomplicated cystitis with damp-heat pattern, summer dehydration with scant dark urine, mild summer diarrhoea with damp-heat, heat rash or prickly heat in hot weather. The formula targets the underlying TCM pattern producing these symptoms rather than the symptom in isolation, which is why pattern diagnosis by a qualified herbalist is essential.

How does Liu Yi San work?

The herbs in Liu Yi San work together: Hua Shi (talc, 18 30g) — chief; clears summer heat and drains damp through urination; Gan Cao (Rx. Glycyrrhizae, 3 5g) — clears heat; resolves toxin; protects fluids; harmonises. The synergy of these actions addresses the underlying TCM pattern.

How long does Liu Yi San take to work?

For most patients, an improvement is typically noticed within 2–4 weeks of daily granule treatment. Full benefit usually requires 6–12 weeks, depending on how long-standing the underlying pattern is. Liu Yi San is typically prescribed as part of an individualised treatment plan that may include other herbs or adjustments over time.

Is Liu Yi San safe in pregnancy?

Use of Liu Yi San in pregnancy should only be considered under the supervision of a qualified RCHM herbalist with pregnancy training, and only when the TCM pattern specifically calls for it.

Who should not take Liu Yi San?

Severe heatstroke (core temperature above 40°C, confusion, collapse) is a medical emergency — call 999, do not rely on herbs. Acute pyelonephritis (fever, loin pain, vomiting) requires urgent antibiotics — herbs are supportive only. Hua Shi should be wrapped during traditional decoction; granule form bypasses this issue. Not appropriate for Yang-deficient cold patterns or pure Yin-deficient thirst without summer Heat. Always consult a qualified Chinese herbalist registered with the RCHM. Prefer to be treated from home? Chinese herbal medicine online consultations are available throughout the UK and worldwide. Liu Yi San must be prescribed only after full pattern diagnosis by a qualified RCHM herbalist; self-prescription is not appropriate.

References

[12] Zhai X, He Q, Chen M, Yu L, Tong C, Chen Y, et al. Pinellia ternata-containing traditional Chinese medicine combined with 5-HT3RAs for chemotherapy-induced nausea and vomiting: A PRISMA-compliant systematic review and meta-analysis of 22 RCTs. Phytomedicine. 2023 Jul;115:154823. https://doi.org/10.1016/j.phymed.2023.154823. PMID: 37099981.