Alzheimer’s disease (AD) is a common neurodegenerative disease that tends to occur in the elderly. The main symptom is hypomnesia. More and more older people are suffering from this disease worldwide. By 2050, 152 million people worldwide are expected to have AD. It is thought that the aggregation of amyloid-beta peptides and hyper-phosphorylated tau tangles contribute to AD. The microbiota-gut-brain (MGB) axis appears as a new concept. The MGB axis is a collection of microbial molecules produced in the gastrointestinal tract that influence the physiological function of the brain. In this review, we discuss how the gut microbiota (GM) and its metabolites affect AD in different ways. Dysregulation of the GM has been shown to be involved in various mechanisms involved in memory and learning functions. We review the current literature on the role of the entero-brain axis in the pathogenesis of AD and its potential role as a future therapeutic target in the treatment and/or prevention of AD.