Chemotherapy-induced hypertriglyceridaemia (HTG) is a potential serious adverse event. Severe HTG with triglycerides (TG) >11.3 mmol/L (1000 mg/dL) can cause acute pancreatitis in addition to cardiovascular diseases such as coronary artery disease. While the association of capecitabine (5-fluorouracil (5-FU) prodrug) with clinically relevant HTG is a well-known adverse reaction, 5-FU is not typically associated with HTG. We here report the case of a patient who developed 5-FU-associated grade 4 HTG with TG level raising up to 37.1 mmol/L (3286 mg/dL) occurring after the ninth cycle of adjuvant FOLFOX (Fluorouracil and Oxaliplatin) chemotherapy. Fenofibrate treatment and diet were started. Chemotherapy was postponed and then resumed for two additional cycles. However, severe HTG recurred shortly after. Chemotherapy was therefore permanently stopped. Approximately 8 weeks after chemotherapy discontinuation, TG fell back to range at 2.1 mmol/L (189 mg/dL) allowing interruption of fenofibrate without HTG recurrence at 3 months.