Inclusion Criteria:  Healthy people age 18-60 years old and do not have regular medication. Able to give the consent formation in a study and to cooperate in answering questionnaires or data records in google formation. The participants must not have any wounds, tattoos, inflammation or pathology on the oral mucosa and skin of testing area. The participants who can come to follow up for a specified period of time.  Exclusion Criteria:  The participants who need dental treatment or necessary to use topical medication to treat oral diseases during the study period (7 days). History of allergic to the components of mucoadhesive film and/or have a history of other allergies. The vulnerable participants include pregnancy or lactating women and disabilities. History of using antihistamines drugs during the one-week period prior to joining the study or participants who need to use such antihistamines during the time participating in the study. History of using topical gluco-corticosteroids during the one-week period on skin testing areas.