PROBLEM TO BE SOLVED: To provide methods and compositions of blocking or neutralizing microorganisms causing infectious diseases so as not to come into contact with or contaminating the mucosa, thereby preventing the microorganisms from spreading within the body and causing infectious disease.SOLUTION: The present invention provides a barrier-forming composition comprising: a carbohydrate gum; a humectant; and an antimicrobial agent, wherein the composition meets the following requirements: about 0.01%≤C≤about 0.4%; about 4.5%≤H≤about 65%; and 0.050%≤A≤1%, wherein all of the above percentages refer to % by weight in the entire composition, wherein C is the carbohydrate gum; H is the humectant; and A is the antimicrobial agent. The barrier-forming composition has antimicrobial or bacteriostatic activity for a duration of about two hours to about six hours when applied to a mammal mucosa, and is safe for human consumption in a therapeutically effective dose.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2017,JPO&INPIT【課題】感染症を引き起こす微生物が粘膜に接触又は汚染しないよう遮断又は中和し、それにより微生物が体内に拡散し感染症を引き起こすことを防止する方法及び組成物の提供。【解決手段】バリア形成組成物であり、炭水化物ガムと、湿潤剤と、抗菌剤とを含み、前記組成物は下記の要件を満足し、約0.01%≦C≦約0.4%、約4.5%≦H≦約65%、かつ0.050%≦A≦1%、上記パーセンテージは全て前記組成物全体における重量%を指し、Cは前記炭水化物ガム、Hは前記湿潤剤、Aは前記抗菌剤であり、哺乳動物の粘膜に塗布したときに、約2時間~約6時間の持続時間にわたって浮遊細菌に対して殺菌活性又は静菌活性を有し、治療有効投与量においてヒトの食用として安全である、バリア形成組成物。【選択図】図1