Crohn''''s disease is a disease characterized by inflammation (the changes that happen when tissues in the body are injured) and ulceration (formation of pus) of the bowel. The purpose of this study is to investigate the safety and therapeutic effect of two different doses of an anti-TNFα (tumor necrosis factor) antibody (a protein) given multiple times compared to a single dose followed by placebo (inactive substance). The name of the antibody is infliximab (Remicade) The goal of the study is to evaluate whether patients respond longer to a single dose of infliximab or to repeated doses of infliximab.

Subjects will receive an infusion of infliximab at week 0 followed by infusions of infliximab or placebo at weeks 2, 6, 14 and every 8 weeks until week 54. Patients who lose response are eligible for additional infliximab treatment.

Inclusion Criteria: - Men and women >=18 years of age - Diagnosis of Crohn''''s - Crohn''''s disease of at least 3 months duration, with colitis, ileitis, or ileocolitis, confirmed by radiography or endoscopy.

Exclusion Criteria: - Local manifestations of Crohn''''s disease such as strictures, abscesses, or other disease - surgery for bowel diversion with placement of a stoma within 3 months prior to beginning the study - positive stool culture