1. A barrier-forming composition comprising: carbohydrate gum； moisturizer and antimicrobial agent； which meets the following requirements: about 0.01% ≤ C ≤ about 0.4%； about 4.5% ≤ H ≤ about 65% and 0.050% <； A about 0% ≤ C ≤ about 0.4%； about 55% ≤ H ≤ about 65% and 0.050% <；A, where all percentages are based on the total weight of the composition and C is a carbohydrate gum； H is a moisturizer and A is an antimicrobial. 2. A barrier-forming composition according to claim 1, which when applied to a human mucosa forms a film with an average thickness of from about 0.001 to about 0.2 mm. The barrier-forming composition according to claim 1, which, when applied to the mucous membrane of a mammal, has an antimicrobial bactericidal or bacteriostatic effect lasting from about 2 to about 6 hours based on in vivo testing. The barrier forming composition according to claim 1, wherein the antimicrobial agent is selected from the group consisting of the following: biguanides, bisbiguanides, polyhexamethylene biguanides or pharmaceutically acceptable salts thereof. The barrier forming composition according to claim 1, wherein the antimicrobial agent is a quaternary ammonium cationic compound or a pharmaceutically acceptable salt thereof. The barrier forming composition according to claim 1, which meets the following requirement: about 0.06% ≤ A ≤ about 0.1% .7. A barrier forming composition according to claim 1, which has a Weybridge viscosity of from about 16 to about 20 cps. The barrier forming composition according to claim 1, wherein the carbohydrate gum has a total negative charge. The barrier forming composition according to claim 1, which has a pH of from 4 to 8.10. The barrier forming composition according to claim 1, in1. Формирующая барьер композиция, включающая:углеводную камедь；увлажнитель ипротивомикробное средство；которая отвечает следующим требованиям:примерно 0,01% ≤ C ≤ примерно 0,4%；примерно 4,5% ≤ H ≤ примерно 65% и0,050% <； Aилипримерно 0% ≤ C ≤ при
