Leukocytapheresis is a controversial nonpharmacologic treatment for IBD, in which white blood cells--the effector cells of the inflammatory process--are mechanically removed from the circulation. Current controversy centers on the uncontrolled nature of the leukocytapheresis trials performed and their use of different outcome measures in patient groups that have very variable disease activity and severity. Nonetheless, the efficacy data obtained are generally quite consistent: an excellent response (remission >80%) has been achieved in corticosteroid-naïve patients with ulcerative colitis and an average remission rate of more than 50% has been achieved in patients who have steroid-dependent or refractory ulcerative colitis. Interestingly, the largest randomized, double-blind, sham-controlled study of granulocyte-monocyte apheresis in patients with moderate to severe ulcerative colitis failed to demonstrate efficacy for the induction of clinical remission or response. Regardless, leukocytapheresis seems to be remarkably safe. The precise positioning of leukocytapheresis in the treatment of ulcerative colitis is uncertain at present and will vary according to geography and patient preference for a safe, nonpharmacologic treatment. Further efficacy studies are required to assess what the optimal number and frequency of treatments is, in addition to the need for head-to-head comparisons with established drugs.