Objectives: The aim of this study was to investigate deodorizing effectsof medicinal herbs (Mume Fructus, Eriobotryae Folium, Acanthopanacis Cortex, Angelicae Dahuricae Radix) for development of a gargle solution. Methods: 1. The antimicrobial effects of medicinal herbs were evaluated with the minimal bactericidal concentration (MBC) and the change of the number of viable cells in the herb extracts(1%) for 48 hrs against P. gingivalis 2561 and Pr. intermedia ATCC 25611. 2. Deodorizing activity of each herb and Garglin $Mint^{(R)}$gainst methyl mercaptan were analyzed by gas chromatography (GC). 3. We used the malodor modeling of the salivary sediment system with a Halimeter. 4. In the preliminary clinical study, the baseline concentration of VSC in the oral cavity of each subject was measured by Halimeter. Subjects would gargle for 30 seconds with cysteine. After 4 minutes subjects would gargle for 30 seconds with Garglin and herb extracts (2%). Subsequently, concentration of VSC were measured at 0, 4, 8, 12 and 20 minutes. Results: 1. MBC of Mume Fructusfor P. gingivalis 2561 was determined to be <1% and MBCs of Eriobotryae Folium for P. gingivalis 2561 and Pr. intermedia ATCC 25611 were determined to be <2% and <1%, respectively. Mume Fructus (1%) completely suppressed the P. gingivalis cell viability from 5 hrs and Eriobotryae Folium (1%) completely suppressed the Pr. intermedia cell viability from 48 hrs. 2. In GC analysis, deodorizing activities were 91.54% with Mume Fructus, 87.97% with Eriobotryae Folium, 100% with Acanthopanacis Cortex, 72.36% with Angelicae Dahuricae Radix and 40.54% with Garglin $Mint^{(R)}$. 3. In malodor modeling of the salivary sediment system, each of the medicinal herbs had significantly inhibitory effect on malodor formation (p<0.05). 4. In the preliminary clinical study, the concentration of VSC of the herb groups was significantly lower than of the control group, but not in Garglin $Mint^{(R)}$. Conclusions: Mume Fructus, Eriobotryae Folium, Acanthopanacis Cortex and Angelicae Dahuricae Radixhave deodorizing activities and potential as an effective mouthwash against oral malodor.