Efficacy of an Oral Formula in Prevention of Anti-cancer Therapy Side Effects

Inclusion Criteria: * Patient with GI neoplasm * Patient that must start a (new) line of chemotherapy with at least 2 cycles * Age \> 18 ans * Exclusively orally fed * Life expectancy more than 3 months * Intravenous 5FU-based chemotherapy with 2 or 3-week cycles * Hematological toxicities from previous chemotherapies terminated or \<= 2 Exclusion Criteria: * Positive HIV status * Pregnant or lactating woman * Currently participating or having participated in another clinical trial during the last month prior to the beginning of this study * Patient having diarrhoea of grade \> 1 for more than 2 weeks before the inclusion * State of sub occlusion, chronic inflammatory diseases of the digestive tract, radiation enteropathy * Sepsis * Concomitant radiotherapy, except analgesic radiotherapy