Thalidomide was first used in the late 1950s but it was withdrawn from the 
market in the 1960s for its notorious teratogenic effects. This drug was more 
recently rediscovered as a powerful immunomodulatory and antiinflammatory agent 
and was approved by the FDA in 1998 for treatment of erythema nodosum leprosum. 
Thalidomide has shown great promise in advanced or refractory multiple myeloma 
either alone or in combination with other agents. It has also demonstrated 
benefits in a wide variety of disparate conditions such as aphthous and genital 
ulcers, cancer cachexia, HIV, tuberculosis and chronic graft versus host 
disease. Thalidomide is being investigated for treatment of renal cell 
carcinoma, and liver and thyroid cancers. Better understanding of its many 
mechanisms of action has provoked great interest in its potential use for 
treatment of various disorders. This review focuses on thalidomide's mechanisms 
of action, biochemistry, pharmacokinetics and its use in erythema nodosum 
leprosum as well as multiple myeloma, graft versus host disease, and renal cell 
carcinoma.