One of the urgent problems of modern health care is Alzheimer's disease (AD) and its early diagnosis. This is due to the rapid global spread of AD, the lack of pathogenetic therapy, and the ability to stabilize the progression of cognitive impairment in the early stages of the disease. Currently, only an autopsy can confirm the diagnosis of AD with 100% reliability, and classical laboratory and instrumental methods of diagnosis verification are difficult to implement in routine clinical practice due to several limitations. That is why the study of new and available biomarkers identified in human bodily fluids is promising for the early diagnosis of AD. The review addresses the problem of AD verification using markers in human bodily fluids, which can be obtained in a non-invasive way. Potential biomarkers of AD in saliva, tear fluid, urine, and nasal secretion are reviewed, and their prognostic values as AD indicators in the early stage are evaluated.