Hata R, Noguchi S, Kawanami T, et al. - Researchers conducted this investigation to explore the link between poor oral hygiene and increase in obligate anaerobes in the lungs of pneumonia patients. The study sample consisted of 39 patients with pneumonia in whom bronchoscopic examination and oral hygiene assessment were performed using oral hygiene index (OHI), tongue coating score, oral dryness, and community periodontal index of treatment needs (CPITN). Increased oral dryness, OHI, and CPITN, but not the tongue coating score, significantly connected with higher detection rates of obligate anaerobes, although no significant relations were noted between the detection of oral streptococci in the lungs and each oral hygiene assessment. In patients with total oral hygiene score of ≥ 5, a significantly higher number of obligate anaerobes were identified in the lungs. According to this prospective study, poor oral hygiene in the lungs of pneumonia patients is associated with increased obligate anaerobes.