Given that Taiwan's National Health Insurance Reimbursement Policy requested physicians to perform eradication of H. pylori infection depending on gastrointestinal endoscopy biopsy with or without 13C-urea breath test and neurologists to treat worsening of AD patients with anti-cholinesterase treatment according to repeated neuropsychological assessment and detailed expert review, we were allowed to observe the impact of eradication of H. pylori on the AD course. This evidence concerns the gene BCHE and Alzheimer disease.