biostudies-literatureAkahori YTakeda Science FoundationJapan Society for the Promotion of Sciencee0312500https://www.ebi.ac.uk/biostudies/studies/S-EPMC11515972biostudies-literatureUnknown19(10)Community-acquired pneumonia is caused primarily by bacterial infection. For years, antibiotic treatment has been the standard of care for patients with bacterial pneumonia, although the emergence of antimicrobial-resistant strains is recognized as a global health issue. The traditional herbal medicine Kampo has a long history of clinical use and is relatively safe in treating various diseases. However, the antimicrobial effects of Kampo products against pneumonia-causative bacteria remain largely uncharacterized. In this study, we investigated the bacteriological efficacy of 11 Kampo products against bacteria commonly associated with pneumonia. Sho-saiko-To (9), Sho-seiryu-To (19), Chikujo-untan-To (91) and Shin'i-seihai-To (104) inhibited the growth of S. pneumoniae serotype 3, a highly PloS oneAntibacterial effects of Kampo products against pneumonia causative bacteria.PMC1151597221K15654Shizuno KAkahori YNagasawa MHashimoto YfalseAntibacterial effects of Kampo products against pneumonia causative bacteria.Community-acquired pneumonia is caused primarily by bacterial infection. For years, antibiotic treatment has been the standard of care for patients with bacterial pneumonia, although the emergence of antimicrobial-resistant strains is recognized as a global health issue. The traditional herbal medicine Kampo has a long history of clinical use and is relatively safe in treating various diseases. However, the antimicrobial effects of Kampo products against pneumonia-causative bacteria remain largely uncharacterized. In this study, we investigated the bacteriological efficacy of 11 Kampo products against bacteria commonly associated with pneumonia. Sho-saiko-To (9), Sho-seiryu-To (19), Chikujo-untan-To (91) and Shin'i-seihai-To (104) inhibited the growth of S. pneumoniae serotype 3, a highly 2024-01-01T00:00:00Z20242026-07-15T14:44:15.738Z2026-07-06T03:08:05.776ZS-EPMC115159723946675210.1371/journal.pone.0312500