The goal of this randomized clinical trial is the evaluation of effect of propolis tablet on prevention and treatment of chemotherapy induced oral mucositis. This is a randomized double-blind and placebo-control study. Fifty patients with colon cancer and under the Folfox chemotherapy regimen who are referred to Imam Khomeini hospital in Sari are randomly placed in 2 groups of 25 people (intervention and control group). The first group of patients receive 2 propolis tablets daily up to 21 days (Tab 50mg).The second group receive placebo. All patients are visited at first and then every week until 3 weeks by oral diseases speciallist and oral mucositis is recorded according to WHO and OMAS indices.