Thalidomide was originally used to treat morning sickness, but was banned in the 1960s for causing serious congenital birth defects. Remarkably, thalidomide was subsequently discovered to have anti-inflammatory and anti-angiogenic properties, and was identified as an effective treatment for multiple myeloma. A series of immunomodulatory drugs — created by chemical modification of thalidomide — have been developed to overcome the original devastating side effects. Their powerful anticancer properties mean that these drugs are now emerging from thalidomide's shadow as useful anticancer agents.