Thalidomide was introduced in the early 1950s as a safe over-the-counter sedative, and went on to be prescribed to pregnant women as a morning sickness treatment during the 1950s and 1960s across 46 countries. By 1961, though, negative effects of the drug were becoming evident -- babies were born with severe deformities. Affected babies were often born with shortened arms or legs and with flipper-like hands and feet (a condition called phocomelia); some babies were born with other defects such as malformed eyes, ears, hearts and other organs [source: March of Dimes]. By the time the manufacturer finally pulled the drug, an estimated 100,000 pregnant women had taken it, and an estimated 40 percent of babies exposed to the drug died (either during the pregnancy or shortly after birth) [source: March of Dimes].
Thalidomide does have its uses, although always with the risk of severe birth defects or infant mortality. It's approved for use as a treatment for multiple myeloma, which is a blood and bone marrow cancer, as well as treatment for skin lesions associated with leprosy, and research is underway on its potential treatment for other cancers, HIV-related complications, and autoimmune conditions such as lupus and Crohn's disease.