Evaluation of Health Costs and Resource Utilization

Inclusion Criteria: * Males 18 years of age or older who are not receiving azathioprine or 6 mercaptopurine. * Non-pregnant, non-lactating females, 18 years of age or older. * Females of child bearing potential must have a negative serum pregnancy test prior to randomization, and must use a hormonal (oral, implantable or injectable) or barrier method of birth control throughout the study. \[defined as a minimum of one year since the last menstrual period\]). * Documented diagnosis of CD or UC. * Active disease symptoms at visit 1 defined by: a. CD subjects: HBS \~ 6 UC subjects: PMCS \~ 4. * Current infliximab therapy (naive to adalimumab) or current adalimumab therapy (naive to infliximab ). * A minimum of 13 weeks of infliximab or adalimumab treatment prior to visit 1 at the following dose: * Stable dose of azathioprine, 6 mercaptopurine, methotrexate, and/or 5-aminosalicylates in the 4 weeks prior to visit 1. Exclusion Criteria: * Contraindication to the use of either infliximab or adalimumab. * Current infliximab treatment but not naive to adalimumab or * Current adalimumab treatment but not naive to infliximab. * Infliximab dosing prior to visit 1 was not 5 mg/kg at weeks 0, 2 and 6 and then q8w. * Adalimumab dosing prior to visit 1 was not 160 mg at week 0, 80 mg at week 2, and then 40 mg q2w. * Received any investigational drug within 30 days prior to visit 1. * Serious underlying disease other than CD or UC which in the opinion of the investigator may interfere with the subject's ability to participate fully in the study. * History of alcohol or drug abuse which in the opinion of the investigator may interfere with the subject's ability to comply with the study procedures. * Stools positive for clostridium difficile. * Pregnant or lactating women. * Change in dose of azathioprine, 6 mercaptopurine, methotrexate, and/or 5-aminosalicylates in the 4 weeks prior to visit 1. * Males 22 years of age or less who are receiving azathioprine or 6 mercaptopurine.