A patient, a 62-year-old man, received endodontic treatment of the lower left canine complicated by apical overfilling of Calcipex II. At the second day after the root canal filling, the 14th day after placement of Calcipex II intracanal medication, he complained of a gingival swelling in the treated area. The incisional biopsy of the gingival swelling revealed a foreign body granuloma infiltrated with macrophages engulfing the fine Calcipex II granules but with polymorphonuclear leukocytes (PMNs). However, the gingival swelling was healed uneventfully, and the tooth was free of symptoms at 4 months' follow-up. This study first reports the Calcipex II-induced reaction in human periodontium. In the immunohistochemistry using antisera of lysozyme, CD31, CD68, interleukin-8 (IL-8), and poly(ADP-ribose) polymerase 1 (PARP-1), the granule-laden cells are positive for lysozyme, CD31, CD68, and PARP-1, but negative for IL-8. Thus, it is presumed that the granule-laden cells belong to the macrophages/monocytes rather than the PMNs, and that they gradually undergo the apoptotic processes. These data suggest that the canal dressing material, Calcipex II, is able to be widely dispersed into the periodontal tissues, primarily engulfed by macrophages, and resulted in the foreign body granuloma in the absence of acute inflammatory reaction.