This study was a quasi-experimental research. To study the effectiveness of ice-chips in the prevention and alleviationof oral mucositis in cancer patients receiving chemotherapy. Studies in patients diagnosed with colorectal cancer. Outpatient treatment and chemotherapy of 5-Fluorouracil and Leucovarin 5 consecutive days Each set was 28 days apart and included 6 sets. The samples were 100 samples divided into 2 groups. The control group consisted of 50 regular caregivers. And50 experimental groups. The subjects were given ice-chips before chemotherapy for 5 minutes and continued for 30 minutes for 5 consecutive days. Evaluation of oral mucositis before chemotherapy. And oralmucositis after chemotherapy. From the new scoring system of Sonis, the authors of the tool adapted from the WHO index and the National Cancer Institute system for the observation of oral mucositis. Suvarn Charoensrichsawat. Translated and adapted to thai people. The research found that Patients with cancer while receiving chemotherapy. Less than oral mucositis. The control group was significantly (p <0.05) less severe than the control group. Compared to the severity of oral mucositis. Between two groups Found that on 2,3,4. There was no statistically significant difference at the end of the experiment. On day 5, the experimental group had a significantly lower mean score of oral mucositis than that of the control group (p=0.005) It is also found that the method of ice-chips is easy, patients and relatives can follow the easy and continuous. It will be used as a guideline to continue