Plaque is a soft deposit substance which attaches to the tooth surface. Plaque is the main cause of caries and periodontal disease. It is needed to prevent the accumulation of plaque. The effort to prevent the plaque accumulation can be by mechanical control, chemical control, and soft viber control. Strawberry is the natural alternative that can be used to prevent the accumulation of plaque. Consuming strawberry can produce the friction of tooth and fruit fibers and the sour taste of strawberry can stimulate the saliva. The chemical substance contained in strawberry is ketakin that can inhibit bacteria growth in a bactericidal way, especially Streptococcus mutans. The aim of the study is to know the effect of consuming strawberry (Fragaria x ananassa) towards plaque formation. The method of the research is experimental quasy with pre-post test control group design. The subjects are 16 students of Dental School Universitas Muhammadiyah Yogyakarta. The data are collected from before and after consuming strawberry using O’Leary plaque index. The data is analyzed using paired t-test. The result of this study is there are significant result which is p=0,000 (<0,05) between before and after consuming strawberry. The conclusion is consuming strawberry (Fragaria x ananassa) effects to decreasing plaque index.