This study is the clinical part of chitosan effect in the treatment of fungal infections which is a continuation of laboratory studies and is consistent with the standards of material handling.Forty patients who wear full dentures with denture stomatitis type two, randomly selected by an examiner. Patients shouldn't give history of anti-fungal therapy, medicines that reduce saliva and history of immunosuppressive disease from a month ago.Patients, divided into two equal groups and first group should use mouth wash chitosan 1% four times a day, each time 2 ml, for two minutes untill two weeks. Another group should use Nystatin as exactly the same way.Palatal smear from infected areas will be obtained,four samples from each patient before and after treatment,Patient, wil physical examine in three stages (pre-treatment, one week later and after treatment) and will take photography.The samples will be analyzed mycologicly. Myslyal form, usually caused by denture stomatitis and blastospore form can be seen at the normal palatal mucosa.Accordingly,palatal smear containing mycelium, also based on clinical signs of infection,lack of erythematosus areas mean healing, reduce erythematosus areas mean relative improvement and no change means no improvement.Also, the patient's pain is a factor to assess recovery and The patient will be checked by completing the form Visual Analog Scale.