Although geriatric diseases are complicated due to the coexistence of many diseases,they often have a common pathological basis and are closely related to the pathogenesis of deficiency and excess in traditional Chinese medicine.Exploring the characteristics of the pathogenesis of deficiency and excess diseases in the elderly is helpful to keep simplicity and restrain complexity,grasp the law of occurrence and development of diseases in the elderly as a whole,and give full play to the advantages of traditional Chinese medicine in the prevention and treatment of chronic diseases.Based on the fundamental characteristics of deficiency and excess in senile diseases,researcher Hu Jingqing further summarized that"essence deficiency,Yin deficiency,Yang deficiency,qi deficiency,blood deficiency"and"qi stagnation,phlegm dampness,blood stasis,fire and heat,and latent wind"are the most common pathogenesis in the occurrence and development of senile diseases.Among them,deficiency is the basic pathogenesis of senile diseases,especially deficiency of kidney essence.Excess disease is the key pathogenesis of the development and changes of senile diseases.Qi stagnation is often the initial step in the development of senile diseases.Phlegm dampness and blood stasis are the pathological products of"excess due to deficiency"and are also the main secondary pathogenesis of senile diseases.In clinical identification of senile diseases,attention should be paid to grasping the pathogenesis of deficiency and excess and its concurrent changes.