Anti-cancer treatment is often inducing side-effects that can affect the compliance to the treatment protocol and quality of life of the patients. The researchers will study if the nutritional intervention with the product could abrogate the undesired effects in a preventive manner.

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