['Aspiration of oral secretions and their bacteria is increasingly being recognized as an important factor in pneumonia. We investigated whether oral care lowers the frequency of pneumonia in institutionalized older people.', 'Survey.', 'Eleven nursing homes in Japan.', 'Four hundred seventeen patients randomly assigned to an oral care group or a no oral care group.', "Nurses or caregivers cleaned the patients' teeth by toothbrush after each meal. Swabbing with povidone iodine was additionally used in some cases. Dentists or dental hygienists provided professional care once a week.", 'Pneumonia, febrile days, death from pneumonia, activities of daily living, and cognitive functions.', 'During follow-up, pneumonia, febrile days, and death from pneumonia decreased significantly in patients with oral care. Oral care was beneficial in edentate and dentate patients. Activities of daily living and cognitive functions showed a tendency to improve with oral care.'] Does oral care reduce pneumonia in older patients in nursing homes?