Yokukansan (written as 抑肝散 and read as Yokukansan in Japanese while YiganSan in Chinese) is a standard recipe or prescription from traditional Chinese medicine used widely in Eastern Asian countries including China, Taiwan, North and South Koreas and Japan.
[4] 薛鎧 (Xue Kai), the father of 薛己 (Xue Ji) explained this recipe in his text book 保嬰撮要 (Bao ying cuo yao) thus: "This recipe improves convulsion, fever, gnash, unsettled state of mind, and terror caused by enervation.
Also, it is effective for vomiting, feeling of fullness, appetite loss and dysnystaxis caused by stress".
In 2005, the efficacy of YKS for behavioral and psychological symptoms of dementia (BPSD) such as hallucination, delusion, easy to anger and so on in demented patients was reported in randomized controlled study (RCT),[4] and meta-analysis showed the same result.
Though 227 medical papers are hit in PubMed on 27 March 2021, the whole mechanisms of YKS efficacy are still not perfectly clear.