Prevalence of dementia above age of 65 years is very high. Due to the unavailability of an effective screening tool in most of the primary care practices, majority of the elder patients with early dementia are undiagnosed. Despite the advances in the field of dementia research, no pharmacologic agents were found to be beneficial in Alzheimer's disease. Sulphur containing derived amino acid homocysteine (Hcy) has been demonstrated well in human ailments. Vitamins such as B6, folate and B12 deficiency were manifested as one of the etiological factors for hyperhomocysteinemia (HHcy) in elder people. Though the folic acid plus vitamin B12 therapy was effective in reducing the HHcy, their effect on dementia or Alzheimer's disease is debatable. This review article discusses the recent observation on the effect of vitamin therapy on HHcy in dementia.