This is a randomized, double-blind, parallel group, placebo-controlled study evaluate the preliminary efficacy and safety of MB-6 (320 mg/capsule, 6 capsules tid) versus placebo in addition to standard chemotherapy in the treatment of patients with metastatic colorectal cancer.

Inclusion Criteria:

1. Patient with histologically confirmed colorectal cancer and/or clinical evidence of metastasis;
2. At least one measurable lesion either by computer tomography (CT) scan or magnetic resonance imaging (MRI);
3. Aged 20 years old or above;
4. Eastern Cooperative Oncology Group (ECOG) performance status < 2;
5. Adequate bone marrow reserve (hemoglobin > 9 g/dl, absolute neutrophil count > 1.5 x 109/L, platelets > 100 x 109/L);
6. Adequate renal and hepatic functions: total bilirubin < 1.25 x upper normal limit, creatinine < 1.25 x upper normal limit, alanine aminotransferase (ALT) or aspartate aminotransferase (AST) < 2.5 x upper normal limit;
7. Patients willing to participate in the trial and giving written informed consent.

Exclusion Criteria:

1. Pregnant or lactating patients;
2. Patients (male or female) with reproductive potential not using adequate contraceptive measures;
3. Patients with evidence of central nervous system metastasis;
4. Subject with active infection which requires systemic treatment of antibiotic, antifungal, or antiviral agents
5. Current history of chronic diarrhea;
6. Other serious illness or medical conditions (e.g.: history of angina, myocardial infarction);
7. History of second primary malignancies except for adequately treated basal cell carcinoma of the skin or carcinoma in situ of the cervix;
8. Concurrent treatment with any other anticancer therapy;
9. Patients with congestive heart failure (New York Heart Association Functional Classification III or IV), epilepsy, or other significant medical conditions as judged by the investigator;
10. Patients treated with another investigational drug within 4 weeks of entry into this study.

16 weeks