OBJECTIVE: To use a gargle to treat anaerobic and other bacterial infection of oral cavity. METHODS:Dual-wavelength isobestic point spctrophotometry was used as the quantitative analysis method. Joel-Dvis method was used to study the stability. RESULTS: The content of tinidazol (TN ) was detected in wave length 317 nm directory Chlorhexidine acetate(CA) was assayed in wave length 254 nm and wave length 273 nm using dual-wavelength isobestic point spctrophotometry. Good recovery was noted when the detective concentration was less than 10 mg·L^-1. The degration ratio of TN and CA was 5.95%and 7.30% respectively after 3-month stability test. CONCLUSION: The preparation's taste, quantitative analysis and stability are well acceptable. The clinical efficacy will be verified in the next study.