Methotrexate is established as an effective treatment for inducing remission or preventing relapse in Crohn's disease. This review discusses the mechanisms of action, pharmacokinetics and clinical trials as well as considering the comparative efficacy between thiopurines and methotrexate. Comparisons are made with the treatment of rheumatoid arthritis. Its role in ulcerative colitis and potential toxicity are addressed. At present, the role of methotrexate is in the treatment of active or relapsing Crohn's disease for patients who are refractory to, or intolerant of, azathioprine or 6-mercaptopurine.