This study is conducted to determine if using a mouthwash containing propolis, clove oil and chlorhexidine will improve the caries risk of high risk patients in comparison to using a mouthwash containing chlorhexidine only.

A total of 64 patients will be assigned in this study. Patients will be randomly divided into two groups according to type of mouthwash (A) where group A1 patients will use chlorhexidine mouthwash as control group while group A2 patients will use chlorhexidine with propolis and clove oil mouthwash as intervention group with 32 patients in each group. Each group will be further divided into two groups according to times of application (T) where T1 represents patients using the mouthwash once daily for one week every month for 6 months and T2 where patients will use the mouthwash twice daily for one week every month for 6 months with 16 patients in each subgroup.

Inclusion Criteria:

• Patients should be over 18 years of age.
• Patients should be with high caries risk assessment.

Exclusion Criteria:

• Patients with a compromised medical history.
• Severe or active periodontal disease.
• Patients with a diseased salivary gland
• History of allergies or other adverse reactions to chlorhexidine, propolis, bee stings, or clove
• Patients on any antibiotics during the past month

Allocation of mouthwash and times of applications to groups will be done through sealed opaque sequentially numbered containers to ensure absolute concealment.