The optimum regimen of maintenance treatment after first-line chemotherapy in patients with metastatic colorectal cancer （mCRC） is unknown. This study was designed to determine the efficacy and safety of maintenance treatment with capecitabine metronomic chemotherapy plus Chinese Traditional Medicine.

In this Prospective, open-label, randomised controlled trial, the investigators will recruit 159 mCRC patients who have finished 18 to 24 weeks first-line chemotherapy and disease evaluation is SD, PR or CR. The patients will then accept Chinese traditional diagnosis and be randomised into two group, capecitabine metronomic chemotherapy only as control group and the metronomic chemotherapy plus Chinese Traditional Medicine as experimental group. This treatment regimen will be continued until progression, death, or an unacceptable adverse event.

The primary endpoint is progression-free survival (PFS). Secondary endpoints are overall survival (OS), quality of life (QOL) and toxic effects.

Inclusion Criteria:

1. unresectable metastatic colorectal cancer with pathological confirmation.
2. patients have accepted 18-24 weeks first-line chemotherapy and disease evaluation is SD, PR or CR.

Exclusion Criteria:

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