PROBLEM TO BE SOLVED: To provide a pneumococcal infection preventing composition containing ampelopsin as an active ingredient and a composition that suppresses immune tolerance.SOLUTION: The present invention provides a composition for preventing or treating infectious pneumonia, containing ampelopsin as an active ingredient.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2020,JPO&INPIT【課題】アンペロプシンを有効成分とする肺炎球菌の感染予防用組成物及び免疫寛容を抑制する組成物を提供する。【解決手段】アンペロプシンを有効成分として含む感染性肺炎の予防及び/又は治療用組成物。【選択図】図1