Immunosuppressive therapy of inflammatory bowel disease: a historical perspective.

I present the progressive development of treatment with immunosuppressive drugs for Crohn's disease and ulcerative colitis, starting with rationale, failure of corticosteroids for maintenance, early observations, controlled trials, collaborations, toxicity (including fear of neoplasms), and considerations in pregnancy. Emphasis is on 6-mercaptopurine and azathioprine. Observations on methotrexate and cyclosporine are included, as well as advice on when to initiate immunosuppressive therapy, what is occurring currently, and what is expected to occur in the near future.