Main Objective of the Plan: Study of green tea extraction effect in comparison with nistasin on chronic erythematosus candidiasis (denture-induced stomatitis). Secondary Objective of the Plan: Determination of therapeutic effects of green tea on decrease of stomatitis as a result of dentures; Method: This is an open, randomized, controlled, experimental Double Blind Clinical Trial study with 30 patients in two parallel groups, 15 patients will receive nistatin drop and the other ones green tea extract. The patients will be recommended to use mouthwash 4 times a day each time 15-20 drops for 5 min and after that they should prevent from eating and drinking for 30 minutes, and they are suggested to use the drug in two weeks at a specific time. Amount of inflammation and erythema, will be recorded before and after treatment in each session. To determine improvement, we have used two criteria: rating system for density of mycological culture and, erythema surface of palatal mucosa on days 0, 7, 14 after commencement of therapy. After selection of the patients, at each visit, mycological samples will be taken from the palatal mucosa and fitting surface of the denture and will inoculated on Sabouraud's dextrose agar plates. Samples will be taken with sterile cotton swabs and inoculated by rolling the swab over the culture media, then will incubate at 37 ᵒC and after 48hr the colonies will be counted and expressed in terms of densities. At each visit, the erythema of the palatal mucosa will be measured with a graded abslang and will record according to 6-point scale. Method for Preparation of Tea Extraction: Fresh tea leaves were gathered from the farms at North of Iran and transferred immediately to the laboratory and dried in laboratory environment. The dried leaves were milled and the powder was screed to become more uniform and extracted by percolator and hydro-alcoholic solution in 70°, for 24, 48 and 72 hours. The extracted were concentrated by rotary device up to 4.5 in percentage of the dry remaining after filtration. The extraction, calls mother extraction will be kept in a refrigerator. At the time of prescription and usage of patients, every milliliter of the "mother extraction" will be fined by 5 milliliter of distilled water and prepared in 30 milliliter glasses with dropper for one week of usage by the patients. Considering coefficient of mother extraction fine, the prepared solution is for usage of patients with alcoholic degree of less than 4-5 that will have no effect on the experiment. Inclusion criteria: Those with denture stomatitis lesions in active phase (Diagnostic criteria is the swelling and inflammation below the denture surface); Exclusion criteria: Patients with Diabetes mellitus, Immune deficiency such as acquired immune deficiency syndrome (AIDS),As well as those who will benefit antibacterial drug therapy, corticosteroids, radiotherapy, and smokers will be excluded. Manner of blinding: The drugs shall pour in semi-color and semi-shape glasses and their difference shall be distinguished based on the code and a list, provided to a third person, up to decoding. The examiner and analyzer did not know anything about the drug.