Inclusion Criteria:  Male or female with the age > or = to 18 years old. Negative pregnancy test for women with child-bearing potential if applicable (without hysterectomy for example) Information given to the patient who must have signed informed consent Patient with Histologically or cytologically proven gastro intestinal cancer including oesogastric, colo-rectal and pancreatic cancers and planned to be treated with oxaliplatin Patient with metastatic disease not previously treated Patient willing not to take any plant-based therapy during the study (including phytotherapy and gemmotherapy) Previous radiotherapy is authorized if discontinued ≥15 days prior to randomization Sites of disease evaluated within 42 days prior C1 day 1 of chemotherapy with thoracic-abdominal-pelvic CT scan (or abdominal-pelvic MRI and chest X-ray) Patient with ECOG Performance status 0 or 1 Patients with a Life expectancy ≥12 weeks Laboratory results:  Hematologic function:  polynuclear neutrophils ≥ 1.5.109/L platelets ≥100.109/L haemoglobin ≥9 g/dL  Hepatic function:  transaminases ≤2.5 times upper limit of normal (ULN) (≤5 ULN in case of hepatic metastases), alkaline phosphatases ≤2.5 x ULN (≤5 ULN in case of hepatic metastases), total bilirubin ≤1.5 x ULN  Renal function:  creatinemia clearance >50 ml/min (Cockcroft and Gault)  - Patient with Public Health insurance coverage  Exclusion Criteria:  Patients with phenylketonuria Patients with known meningeal or brain metastases Patient previously treated for their metastatic cancer Patient previously treated with oxaliplatin Patient with specific contraindication or known hypersensitivity to spirulina Patient with specific contraindication or known hypersensitivity to oxaliplatin. If Patient is treated with a monoclonal antibody combined to chemotherapy (bevacizumab or cetuximab or panitumumab), known allergy or hypersensitivity to antibodies or any preservatives has to be excluded Patient with clinically significant coronaries affection or myocardial infarction within 6 months prior to randomization. Patient with peripheral neuropathy >1 (CTCAE scale version 5.0). Patients with known dihydropyrimidine dehydrogenase (DPD) deficiency. Patient with acute intestinal obstruction or sub-obstruction, history of inflammatory intestinal disease or extended resection of the small intestine or presence of a colic prosthesis. Patient with unhealed wound, active oesogastric or duodenal ulcer, or bone fracture Patient with an history of abdominal fistulas, trachea-esophageal fistulas or any other grade 4, gastro-intestinal perforations or non-gastrointestinal fistulas or intra-abdominal abscesses during the 6 months before randomization. For patient treated with bevacizumab: patient with uncontrolled arterial hypertension (systolic pressure >150 mmHg and/or diastolic pressure >100 mmHg) with and without antihypertensive medication. Patients with high hypertension are eligible if antihypertensive medication lowers their arterial pressure to the level specified by the criterion. Patient with an history of hypertensive crisis or hypertensive encephalopathy Patient with other concomitant malignancy or history of cancer (except in situ carcinoma of the cervix, or non-melanoma skin cancer, treated with curative intent treatment) except if considered in complete remission for at least 2 years before randomization Existence of any other pathology, metabolic problem, anomaly during the clinical examination or biological anomaly which may reasonable suspect an underlying pathology which would contra- indicate the use of the study medication or any other risk of complication related to the treatment. Any treatment including an experimental drug, or participation in another clinical trial within 28 days before randomization. Pregnant women, or women who could possibly be pregnant (or who expect to fall pregnant within 6 months of the end of treatment), or who are breast feeding are not eligible. Men and women of child-bearing potential who do not accept to use a highly effective contraceptive (as per currently acceptable institutional standards) or abstinence during the study and for the month after the last administration of the study treatments. Persons deprived of liberty or under guardianship. Psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule.