A randomized control trial study was carried out to evaluate the effect of allopurinol mouth wash on stomatitis induced by chemotherapy in gynecologic patients. Chemotherapeutics used consisted of 5-FU+CDDP (PF) given to 10 patients and vincristine and actinomycin-D+cyclophosphamide (VAC) given to 5. Allopurinol mouth wash was prepared for patients to rinse their mouth with the solution 4-5 times daily before and after treatment with anti-cancer drugs. The Japan Society For Cancer Therapy's criteria for stomatitis were used. In the control group, stomatitis occurred in 9 of the 10 patients receiving PF therapy and in all of the 5 receiving VAC. In contrast, stomatitis was observed in only 2 of the 10 patients receiving PF therapy and 2 of the 5 VAC in the allopurinol-treated group. Allopurinol mouth wash showed a marked effect on stomatitis induced by chemotherapy.