To compare pharmacodynamics among the different concentrations of BCS and NS.

2 times mouthwash in the morning and at night. To collect bacterium samples to assess the pharmacodynamics among the different concentrations of BCS and NS: observe the changes of aerobic bacterial colonization in oropharyngeal over time during 24 hours, and assess the improvement of oral healthy status and the subjective feelings after 24 hours.

Inclusion Criteria:

• Healthy volunteers, males or females.
• Females with U-HCG negative.
• Signed ICFs, and could conduct this study with investigators.

Exclusion Criteria:

• History of mouthwash allergies, allergic rhinitis or dermatitis.
• Volunteers with oral ulcers, severe periodontal disease, oral mucosal lesions or oral cancer.
• Volunteers with removable denture.
• Had received special oral clean.