What is Yi Gan San used for?

Yi Gan San (Yokukansan) is used for behavioural and psychological symptoms of dementia (BPSD), Lewy body dementia agitation, tic disorders, Tourette syndrome in children, autism-spectrum irritability, childhood night terrors, and premenstrual or perimenopausal irritability driven by Liver wind from Liver Blood deficiency.

What is the difference between Yi Gan San and Yokukansan?

They are the same formula. Yi Gan San is the Chinese Pinyin name; Yokukansan is the Japanese Kampo name. Both contain the same seven herbs in the same proportions. The Japanese name is more commonly used in modern dementia research.

What is the TCM pattern treated by Yi Gan San?

Yi Gan San treats Liver wind from Liver Blood deficiency with Spleen weakness — irritability, easy anger, muscle twitching, tics, restless or aggressive behaviour, broken sleep with nightmares and a pale or slightly red tongue with thin coat.

Is Yi Gan San safe for children?

Yes, Yi Gan San was originally designed as a paediatric formula and has a long-established safety record in children. It is used for childhood irritability, night terrors, tic disorders and autism-spectrum behavioural difficulties. Always prescribed by an RCHM-registered Chinese herbalist.

Are there any cautions with Yi Gan San?

Yi Gan San is generally well tolerated. Use cautiously in patients on multiple CNS-active medications and monitor potassium in long-term use due to the glycyrrhizin in Gan Cao (licorice), which can cause pseudo-aldosteronism with low potassium at high doses or long courses.

Yi Gan San (抑肝散) — Restrain the Liver Powder (Yokukansan)

Quick answer: Yi Gan San — "Restrain the Liver Powder", known in Japan as Yokukansan — is a classical Ming-dynasty paediatric formula for the TCM pattern of Liver wind from Liver Blood deficiency with Spleen weakness. A systematic review and meta-analysis of RCTs reported reductions in behavioural and psychological symptoms of dementia (BPSD) total scores with Yokukansan compared with controls.^[1]

On this page

Overview
TCM pattern
Key herbs
Formula actions
Conditions treated
Cautions

What is Yi Gan San?

Yi Gan San — Restrain the Liver Powder — is a classical Ming dynasty paediatric formula from Xue Kai’s Bao Ying Cuo Yao (1556). In Japan it is known as Yokukansan and is one of the most extensively studied Kampo formulas. Systematic review and meta-analysis evidence supports its use for behavioural and psychological symptoms of dementia (BPSD).^[1]

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

Yi Gan San TCM pattern

Prescribed for Liver wind from Liver Blood deficiency with Spleen weakness: irritability, easy anger, muscle twitching or tics, restless or aggressive behaviour, broken sleep with nightmares, possible mild tremor, pale or slightly red tongue with a thin coat and a slightly wiry pulse.

Key herbs

Chai Hu (Rx. Bupleuri, 1.5g), Gou Teng (Ram. cum Uncis Uncariae, 3g) — spread Liver Qi and extinguish Wind
Dang Gui (Rx. Angelicae Sinensis, 3g), Chuan Xiong (Rx. Chuanxiong, 2.4g) — nourish and move Liver Blood
Bai Zhu (Fried Rz. Atractylodis Macrocephalae, 3g), Fu Ling (Poria, 3g) — tonify Spleen Qi and drain Damp
Gan Cao (Rx. Glycyrrhizae, 1.5g) — harmonises and supports the middle

Formula actions

Spreads Liver Qi and extinguishes internal Wind
Nourishes Liver Blood
Tonifies the Spleen

TCM patterns and conditions where it is used

The formula is used for the TCM pattern of Liver wind from Liver Blood deficiency with Spleen weakness. The presentations within that pattern include:

Behavioural and psychological symptoms of dementia (BPSD) — agitation, aggression, sleep disturbance — systematic review and meta-analysis evidence supports Yokukansan as adjunct to conventional dementia care^[1]
Lewy body dementia agitation patterns (in clinical practice alongside conventional neurology care)
Liver wind movement-pattern presentations such as tics in children (in TCM clinical practice, alongside conventional care)
Childhood Liver wind-with-Blood-deficiency presentations: irritability, night terrors, behavioural meltdowns
Liver wind irritability patterns in autism-spectrum presentations (adjunctive, alongside conventional care)
Premenstrual and perimenopausal Liver wind irritability patterns

Cautions

Generally very well tolerated. Use cautiously in patients on multiple CNS-active medications; review the combined regimen with the prescribing doctor. Glycyrrhizin in Gan Cao at high doses or long courses can cause pseudo-aldosteronism with low potassium — monitor potassium in long-term use.

Always consult a qualified Chinese herbalist registered with the Register of Chinese Herbal Medicine (RCHM). Online herbal consultations are available.

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

References

[1] Matsunaga S, Kishi T, Iwata N. Yokukansan in the Treatment of Behavioral and Psychological Symptoms of Dementia: An Updated Meta-Analysis of Randomized Controlled Trials. J Alzheimers Dis. 2016;54(2):635-43. https://doi.org/10.3233/JAD-160418. PMID: 27497482.

What is Yi Gan San (Yokukansan) used for?

Yi Gan San (Restrain the Liver Powder, known as Yokukansan in Japan) is the principal Chinese herbal formula for Liver Yang rising patterns with prominent agitation, anger, irritability, restlessness and disturbed sleep. It's now particularly well-evidenced for behavioural and psychological symptoms of dementia (BPSD), including agitation, aggression and night-time disturbance in elderly patients.

Is Yi Gan San safe for elderly dementia patients?

Yes — Yokukansan has been extensively studied in Japanese elderly dementia care and is now included in the Japanese Society of Neurology dementia guidelines. Multiple randomised controlled trials have documented significant reductions in BPSD scores with low rates of adverse effects compared to antipsychotic medication. The formula does not produce the sedation, extrapyramidal effects or increased mortality associated with antipsychotics in elderly dementia patients.

How does Yi Gan San differ from antipsychotic medication for agitation?

Antipsychotic medications (haloperidol, risperidone, quetiapine) suppress symptoms through dopamine receptor blockade but carry serious risks in elderly patients including increased stroke and mortality. Yi Gan San addresses the underlying Liver Yang rising pattern through Liver Blood nourishment and gentle anchoring of Shen. Improvement is more gradual but more sustainable, with markedly lower adverse-effect burden. The two can be combined in severe cases under specialist supervision.

Can Yi Gan San help children with autism or ADHD?

Yes — the formula is also used in paediatric practice for the Liver Yang rising or Liver Wind picture in some children with autism-spectrum behaviour difficulties, ADHD with irritability, or persistent severe tantrums. Treatment uses age-adjusted paediatric doses with careful pattern differentiation. Always combine with paediatric specialist care; herbal treatment is supportive, not curative.

How long does Yi Gan San take to work for agitation?

Most patients with significant agitation see meaningful improvement within 4–6 weeks of daily treatment, with progressive deepening of effect over 3–6 months. In elderly dementia patients, the dosing is typically lower and the response slower but more sustained. For acute severe agitation, the formula is used alongside (not instead of) appropriate conventional crisis management.