Proton pump inhibitor (PPI) is an effective and safe medication for the elderly people for the treatment of peptic ulcer disease. However, some PPIs have been reported that they have metabolic interactions with some drugs. Therefore, drug-interactions should be considered when the PPI is prescribed to the elderly people. The number of NSAIDs ulcer patients is thought to increase along with the increase of those who take NSAIDs in the elderly. Although PPI is indispensable for the prevention of the NSAIDs ulcer, PPI has not obtained authorization for the purpose of prevention in Japan. PPIs are strongly expected to be approved for prevention of NSAIDs ulcer by the Japanese government in the near future.