Guillain-Barré syndrome (GBS) is an acute neuropathy and a clinical syndrome that includes a number of pathological and electrophysiological subtypes. Intravenous immunoglobulin (IVIG) and plasma exchange (PE) are both equally efficacious for the treatment of GBS; however, the cost of IVIG may be lower for both the patient and the healthcare system. To compare the pharmacoeconomics of PE and IVIG in GBS, a retrospective study was done from 1999 to 2004, which included a total of 24 patients with GBS who were admitted to Taipei Veterans General Hospital. This showed that except for the costs of the drugs used in IVIG, treatment of GBS with IVIG was more cost-effective (p=0.057) than that with PE in total length of hospitalization and the cost of procedures and hospitalization. The study also showed that the total costs were higher for patients on ventilators than those not requiring ventilators (p=0.008, t-test) and the length of hospitalization showed a very strong linear relationship to total costs (Pearson correlation coefficient=0.907). The regression analysis showed that each additional day of hospitalization increased the hospitalization costs by an average of 5599 New Taiwan Dollars (NT) (US$1.00=NT$33.50 in 2005).