Objectives: In this study the untifungal effect of Green tea mouthwash 0.5% on patients with denture stomatitis was examined. Design: Twenty two patients with denture stomatitis who had been referred to the department of oral medicine in sari faculty of dentistry in spring 1396 were divided into two groups. Setting and conduct: One group received treatment with green tea mouthwash 0.5% four times a day and each time use 15 milliliter about 2.5 table spoon for two weeks. Another group use nystatin suspension 100000 u/l four times a day and each time use 1 milliliter about 20 drops for two weeks. Participants including majoreligibility criteria: Absence of using denture in sleeping; No use of untifungal drugs and antibiotics and corticosteroid in past 1 month; No allergy to nystatin suspension; Absence of immunodeficiency; Absence of alzheimer; Absence of cyhalological disorders; Absence of musculoskeletal disorders; Ability to consume mouthwash. Main outcome messures: First examination is before treatment is run to check the length and the width of lesions.7 days after first examination, in the second examination length and width are written.14 days after first examination, in the third examination length and width are written again.the microbial culture is done before treatment and after 14 days. Finally the data of two groups are compared.