Trial Parameters
Brief Summary
Using a new formulation of rifaximin, a non-absorbable antibiotic, to test if it can affect microbes in the gut of patients with dementia favorably.
Eligibility Criteria
Inclusion Criteria: * Probable Alzheimer's Disease (AD) or Vascular Dementia (VaD) mild or moderate based on Clinical Dementia Rating Scale. * Males and Females Age ≥ 65 years * Community living with availability of caregiver to accompany participant to study visits and to participate in the study. * Able to consent or legal guardian who can consent (with participant assent). * Legally authorized representative (LAR) and caregiver for the study is the same individual. * Fluency (both participant and caregiver) in written and spoken English to participate in study visits. Exclusion Criteria: * Dementia not due to AD or VaD * Clinically significant agitation or aggression (requiring treatment with antipsychotic medication) * Delusions and/or hallucinations * Severe psychopathology including major depression * Unstable, severe, or poorly controlled medical conditions evident from physical examination or clinical history * Visual and/or hearing disorder that prevents completion of neuropsy