Objective: Evaluate toxicity of the adjuvant chemotherapy with Xelox for colon cancer patients. Patients and method: 70 patients with stage III colon cancer were treated by surgery and adjuvant chemotherapy with Xelox at the K hospital and Ha Noi Medical University hospital from 2010 to 2013. The restrospective descriptive study. Results: The hematological toxidty with anemia is 19,64 percent, grade 1(15 percent), grade 2 (3,57 percent), grade 3(1,07 percent). Neutropenia grade 1, 2 is 21,5 percent and 15 percent
grade 3(9,2 percent) and grade 4 is very low. Neutropenia is 15 percent. Neutropenia is most seen in cycle 2, 3, 4. The highest in cycle 4. Thrombocytopenia is low, usually grade 1-2. Enzymes SGPT increase is 14,3 percent and Enzymes SGPT increase is 16,1 percent. Nephrotoxicity is not comment, grade 1-2(10 percent). Other toxicities as diarrhea 10 percent, nausea and vomiting 13,3 percent, hand-foot syndrome 15 percent, alopecia 10 percent. Neurologic sensitive toxicity is 52,5 percent. Conclusion: The common toxicities were anemia, neutropenia, thrombocytopenia, diarrhea, nausea and vomiting, hand-foot syndrome, alopecia, but these toxicities were acceptable and coud be recovered after applying medical treatment