Twenty-five patients with pretreated advanced colorectal carcinoma were subjected to second-line chemotherapy with sequential high-dose methotrexate and 5-fluorouracil. In 20 evaluable patients 2 (10%) partial responses, 12 (60%) stable disease and 6 (30%) progressions were observed. Partial responses were maintained for 3 and 4 months respectively; stable disease had a median duration of 4 months. The overall median survival after progression was 7 months. From our results sequential high-dose methotrexate and 5-fluorouracil cannot be recommended as second-line chemotherapy in advanced colorectal cancer.