Yi Gan San — Restrain the Liver Powder (Yokukansan)

On this page

1. Overview
2. TCM pattern
3. Key herbs
4. Formula actions
5. Conditions treated
6. 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, with Western and Japanese RCTs supporting its use for behavioural and psychological symptoms of dementia (BPSD), Lewy body dementia agitation, autism-spectrum irritability and tic disorders.

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

1. Chai Hu, Gou Teng — spread Liver Qi and extinguish Wind
2. Dang Gui, Chuan Xiong — nourish and move Liver Blood
3. Bai Zhu, Fu Ling — tonify Spleen Qi and drain Damp
4. Gan Cao — harmonises and supports the middle

Formula actions

1. Spreads Liver Qi and extinguishes internal Wind
2. Nourishes Liver Blood
3. Tonifies the Spleen

Conditions treated

1. Behavioural and psychological symptoms of dementia (BPSD) — agitation, aggression, sleep disturbance (with conventional care, evidence from Japanese trials)
2. Lewy body dementia agitation
3. Tic disorders and Tourette’s syndrome in children
4. Childhood irritability, night terrors and behavioural meltdowns
5. Autism-spectrum irritability and self-injurious behaviour (adjunctive)
6. Premenstrual irritability and irritability in perimenopause

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.

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