Alzheimer disease （AD） is a progressive neurodegenerative disease that often occurs in the elderly. The main symptoms of AD patients are cognitive decline， especially memory deficits， communication problems， impaired performance of activities of daily living， and other behavioral and psychological abnormalities. AD is generally divided into familial AD and sporadic AD. The signature features of AD are the presence of amyloid-beta proteins in extracellular plaques. Senile plaques formed by accumulation of Aβ insoluble fragments and intracellular accumulation of highly phosphorylated tau are neurofibrillary tangles. There is a lot of scientific evidence to confirm that the development of the two signature features of AD may be related to naturally occurring microbes in the human body. This paper reviews the mechanism of intestinal， oral and fungal microbiota involved in the development and progression of AD.

Objective To analyze and assess the major functions of medical APP by investigating its application in self management of chronic diseases. Methods The 3 major functions of APP were analyzed, including data record and condition assessment, medical consultation, and life therapy. Results The medical APP possesses its basic functions for chronic diseases management. However, it lacks of practicality and convenience and its homogenization is severe. Conclusion The APP +hardware +cloud medical management model should be promoted by making use of the Internet + medical technology, the supervision of mobile medical APP should be strengthened, the mobile information management mechanisms of chronic diseases should be perfected, and the self management efficiency of patients with chronic diseases should be improved.