This study is designed to:(1) determine the efficacy of Traditional Chinese Medicine (TCM) 'Tonifying Spleen and Kidney Sequential Regimen' (TSKSR) in improving the completion rate of 8-cycle CapeOX chemotherapy in patients with stage II (high-risk)& III colon cancer;(2) evaluate the efficacy of the TCM-TSKSR on adverse events of CapeOX chemotherapy and it's impact on patients' quality of life (QoL).A randomized,double-blinded,placebo-controlled clinical trial including seven centers will be conducted in Mainland China.The study will enroll patients with stage II (high-risk)& III colon cancer who have completed radical surgery and are going to receive CapeOX chemotherapy.All participants will receive chemotherapy as prescribed by their treating physicians and be randomly assigned to either concurrent use of TCM-TSKSR or placebo.

CapeOX chemotherapy is a combination therapy of Oxaliplatin 130mg/m^2 IV on 1st day and Capecitabine 1000mg/m^2 PO twice daily from 1th day to 14th day,21 days for each course of treatment.Adverse effects of chemotherapy,such as myelosuppression and gastrointestinal reactions,may lead to dose reductions,treatment delays or even discontinuation among cancer patients. According to IDEA study,the completion rate of 8-cycle CapeOX chemotherapy in colorectal cancer patients is 64%,which means that nearly 4 in 10 patients could not complete adjuvant chemotherapy as planned,which may negatively impact patients' survival outcomes.Some prior studies have shown that TCM can improve patients' symptom control and QoL during adjuvant chemotherapy,which may further improve the completion of adjuvant chemotherapy. However,there is a lack of definitive evidence to evaluate the effects of TCM in stage II(high-risk)& III colon cancer patients who receive adjuvant chemotherapy after radical surgery.The study will be conducted between 2018 and 2021.Four hundred participants will be enrolled and randomly assigned to either the experimental group or the control group.

Inclusion Criteria:

• Patient with pathological diagnosis of colon cancer; no residual tumor at the resection margin.

• tumor-node-metastasis(TNM)Stage II (high-risk)or III colon cancer according to 8th edition of American Joint Committee on Cancer(AJCC)Staging Manual. High-risk stage II disease is characterized by at least one of the following:

  1. T4 tumor,
  2. inadequately sampled nodes (<12 lymph nodes),
  3. clinical presentation with bowel obstruction or perforation,
  4. poorly differentiated histology ,exclusive of those cancers that are High degree of microsatellite instability(MSI-H),
  5. lymphovascular invasion,perineural invasion(PNI).

• Underwent radical surgery no more than six weeks ago and plan to start chemotherapy.

• Have not been enrolled in other therapeutic clinical trials within the near 30 days.

• Age between 18 to 75 years; All genders; Eastern Cooperative Oncology Group - performance status(ECOG-PS)from 0 to 2; Women who are pregnant, lactating or of reproductive age are not eligible, while those of reproductive age using secure contraceptives are eligible.

• No history of previous malignancy other than adequately treated in situ carcinoma of the uterine cervix or basal or squamous cell carcinoma of the skin, unless there has been a disease-free interval of at least 5 years.

• Laboratory testing: blood routine examination: WBC≥3.5×109/L，NEUT≥1.5×109/L,PLT≥100×109/L,HGB≥90g/L;biochemical tests:TBIL≤1.5×ULN,AST(SGOT),ALT(SGPT)≤2.5×ULN,Scr≤1.5×ULN;CEA after surgery was normal.

• Consented.

• Agree not to be enrolled in other interventional studies during the research.

Exclusion Criteria:

• Patients not suitable for chemotherapy of CapeOX ,which will be determined by the investigator or the attending physician.
• Clinically relevant cardiovascular and/or cerebrovascular disease,active hepatitis,severe abnormalities in liver/ renal function tests.
• Known allergy to any of the components of study drug.
• Those who cannot take the study drug orally because of bowel obstruction and/or require for peripheral vein nutrition.
• Malabsorption or diseases that affect the absorption.
• Unstable situations or situations that may endanger the safety of patients and their compliance, such as severe mental illness,schizophrenia.
• Colostomy