Peel from manggosteen (Garcinia Mangistan Linn) has many benefit. Among them are antioxidant and antibacterial. This is due to the mangosteen Peel (Garcinia Mangistan Linn) contains active compounds such as Xanon, Flavonoid, tanin and saponin. Anti-bacterial from manggosteen peel is able to inhibit the growth of bacteria causes the emergence of plaque. The purpose of this study was to see how far to see how far a decrease in plaque that occurs when skin extract of mangosteen ( Garcinia Mangistan Linn ) 0.05 % is made into a mouthwash. The subject from this study consist of 26 people, than devided into 4 group, each group consist of 6 people (groups based on the length of gargling : 1 minut; 2 minut; 3 minut; control). The changing of index plaque was measured before and after gargling. Data analysis that is used is a one-way Anova (P<0.05. The results from one-way Anova Test there is a significant difference to the formation of plaque from before and after gargling.gargling condacted using mouthwash from Mangosteen peel extract (Garcinia Mangistan Linn.) it can inhibit the establishment of plaque from the first minute, but the result of gargling for 3 minutes will get a more optima