The efficacy and tolerability of raltitrexed ('Tomudex', formerly ZD1694) as a single agent for the treatment of advanced colorectal cancer has been established in a large clinical trial programme. It is now possible to move the drug forward into the treatment of earlier stages of colorectal cancer. In addition, its mode of action lends itself to combination with other agents, not only 5-fluorouracil, but also oxaliplatin and irinotecan for the treatment of advanced disease. Preclinical and early clinical data also suggest that raltitrexed may show activity in a range of other tumour types. Studies evaluating these potential clinical applications of raltitrexed are either planned or already under way.