Yang deficiency is the main cause of most diseases. The treatment of dementia based on syndrome differentiation is also related to Yin-Yang. The authors propose the principle that senile dementia might be treated in sequence. They hold that the treatment of this disease should be combined with clinical stages. In early stage

the location of disease is upper-jiao（ lung）

the main cause is orifices confused by phlegm. Thus

the therapy is dispersing lung Qi and ascending lucidity and descending turbidity. In middle stage

the location of disease is middle-jiao（ spleen and stomach）

the main cause is internal blockade of static blood and deficiency of both heart and spleen Yang. Thus

the therapy is activating blood circulation to dissipate blood stasis and warmly invigorating spleen yang.In late stage

the location of disease is lower-jiao（ kidney）

the main cause is deficiency of kidney Yang and Yin.Thus

the therapy is invigorating essential Qi and warmly consolidating kidney Yang. In this way

Yin and Yang become harmonious

so that there might be good effect.