Guillain-Barré syndrome (GBS) is an acute paralysing disease caused by inflammation of the nerves. Between 3.5% and 12% of people with GBS die of complications during the acute stage. A quarter of patients need artificial ventilation. Recovery takes several weeks or months and is often incomplete. Plasma exchange (washing harmful substances out of the blood) and intravenous immunoglobulin (infusion of human antibodies harvested from blood donations into the blood stream) are beneficial but corticosteroids are not. Since current treatments are insufficient, new methods need to be discovered. We searched for randomised controlled trials of other drugs for GBS. We only found very low quality evidence. One randomised controlled trial with only 13 participants tested interferon beta-1a, a drug which is beneficial in multiple sclerosis. Another with only 10 participants tested a nerve growth factor which theoretically should be beneficial. A third trial with 37 participants compared cerebrospinal fluid filtration (washing the nerve roots around the spinal cord) and plasma exchange. None of these trials was large enough to confirm or refute benefit or harm in acute GBS. A fourth trial with 20 participants suggested that the Chinese herbal medicine tripterygium polyglycoside improved disability faster than corticosteroids but this result needs confirmation with more research. There was very little evidence other than that from randomised controlled trials. There is a need to develop and test new treatments.