The purpose of this study was to emphasize the necessity of gargling for a pleasant oral environment, to examine the changes in the oral environment through the saliva before and after the use of optimal mouthwashes for the most effective and continuous oral care among various mouthwashes, and to improve the oral environment. This study was conducted on 20 female students at a university located in Gangwon Province who did not have any special medication history within the last 6 months and did not smoke. Group 1 (n=5) gargled with 0.2% chlorhexidine gluconate (CHX), group 2 (n=5) with 7.5% Povidone Iodine (PVI), group 3 (n=5) with sodium bicarbonate-normal saline, and group 4 (n=5), the control group, with sterile distilled water. After collecting 10 ml saliva from each group, 15 ml of each solution was used for 1 min, and then 10 ml saliva was collected. The results showed that there was a significant difference in pH in the CHX and PVI groups (p<0.05), and there was a significant decrease in the O’Leary index in the CHX, PVI, and sodium bicarbonate-normal saline groups (p<0.05). In addition, there was a statistically significant difference in Streptococcus mutans (S. mutans) (P<0.05) in the order of the PVI and CHX groups (p<0.05). In terms of the Snyder test, all the groups showed a statistically significant difference (p<0.05). Therefore, it was confirmed that mouthwashes improve the oral environment, and 7.5% PVI was the most effective mouthwash, followed by 0.2% CHX.