Worldwide, more than 50 million people live with dementia, and due to the rapidly aging population, dementia cases are expected to increase at least five times in 2050. 30%–40% of dementia cases are diagnosed as non-Alzheimer’s dementia. Common subtypes of non-Alzheimer’s dementia are known as vascular, Lewy body, and frontotemporal dementia. Despite advances in modern medicine, the mechanism of dementia is still not fully understood. The term “omics” is a general term and is used to comprehensively characterize molecules by functional and biological similarities, focusing on the basic biological processes of a living organism and these techniques have enabled us to examine the unknown areas of biology, such as the genome, transcriptome, proteome, microbiome, and metabolome. This review highlights the progress that has been made in omics research while noting the gaps in our knowledge.