A method for treating a disease or for treating a symptom of a disease, or a combination of both, the disease being caused or aggravated by microorganisms includes: treating the disease, treating the symptom of the disease, or reducing the duration of the disease, or a combination of both by administering a barrier-forming composition in a therapeutically effective amount to a surface, the surface comprising a mammal mucosa, the mammal being infected with the disease or experiencing symptoms of the disease caused or aggravated by the microorganisms. The barrier-forming composition includes an antimicrobial. Upon administering the composition, the method includes forming a barrier coating on the surface that is active to kill or neutralize microorganisms encountered by the barrier coating. A composition with an agent active for relieving symptoms of a disease is also included.
